pi/4 <= |x| <= 3pi/4. Use the same branch ladder as for float precision.
Remove the optimization for |x| near pi/2 and don't do it near the
multiples of pi/2 in the newly optimized range, since it requires
fairly large code to handle only relativley few cases. Ifdef out
optimization for |x| <= pi/4 since this case can't occur because it
is done in callers.
On amd64 (A64), for cos() and sin() with uniformly distributed args,
no cache misses, some parallelism in the caller, and good but not great
CC and CFLAGS, etc., this saves about 40 cycles or 38% in the newly
optimized range, or about 27% on average across the range |x| <= 2pi
(~65 cycles for most args, while the A64 hardware fcos and fsin take
~75 cycles for half the args and 125 cycles for the other half). The
speedup for tan() is much smaller, especially relatively. The speedup
on i386 (A64) is slightly smaller, especially relatively. i386 is
still much slower than amd64 here (unlike in the float case where it
is slightly faster).
saves an average of about 8 cycles or 5% on A64 (amd64 and i386 --
more in cycles but about the same percentage on i386, and more with
old versions of gcc) with good CFLAGS and some parallelism in the
caller. As usual, it takes a couple more multiplications so it will
be slower on old machines.
Convert to __FBSDID().
Maybe. In the meantime, my workarounds for trying to coax UTC without
timegm() are getting uglier and uglier. Apparently, some systems
don't support setenv()/unsetenv(), so you can't set the TZ env var and
hope thereby to coax mktime() into generating UTC. Without that, I
don't see a really good alternative to just giving up and converting to
localtime with mktime(). (I suppose I should research the Perl library
approach for computing an inverse function to gmtime(); that might
actually be simpler than this growing list of hacks.)
now returns a value, which supports such convenient
constructs as:
if (assert(NULL != foo())) {
}
Also be careful to setlocale("C") for each new test to
avoid locale pollution.
Also a couple of minor portability enhancements.
* If the platform can't restore char nodes, block nodes, or fifos,
don't try and just return error.
* Include O_BINARY in most open() calls (define O_BINARY to 0 if the
platform doesn't provide a definition already)
* Refactor the ownership restore to more cleanly support platforms
that don't have any form of {l,f,}chown() call.
* Comment a lingering issue with older Unix-like systems that allow
root to hose the filesystem. I don't (yet) have a good solution for
this, but I expect it will require adding more redundant stat()
calls. <sigh>
MFC after: 14 days
optimization of about 10% for cos(x), sin(x) and tan(x) on
|x| < 2**19*pi/2. We didn't do this before because __ieee754__rem_pio2()
is too large and complicated for gcc-3.3 to inline very well. We don't
do this for float precision because it interferes with optimization
of the usual (?) case (|x| < 9pi/4) which is manually inlined for float
precision only.
This has some rough edges:
- some static data is duplicated unnecessarily. There isn't much after
the recent move of large tables to k_rem_pio2.c, and some static data
is duplicated to good affect (all the data static const, so that the
compiler can evaluate expressions like 2*pio2 at compile time and
generate even more static data for the constant for this).
- extern inline is used (for the same reason as in previous inlining of
k_cosf.c etc.), but C99 apparently doesn't allow extern inline
functions with static data, and gcc will eventually warn about this.
Convert to __FBSDID().
Indent __ieee754_rem_pio2()'s declaration consistently (its style was
made inconsistent with fdlibm a while ago, so complete this).
Fix __ieee754_rem_pio2()'s return type to match its prototype. Someone
changed too many ints to int32_t's when fixing the assumption that all
ints are int32_t's.
reallocation, when junk filling is enabled. Junk filling must occur
prior to shrinking, since any deallocated trailing pages are immediately
available for use by other threads.
Reported by: Mats Palmgren <mats.palmgren@bredband.net>
allocation patterns, number of CPUs, and MALLOC_OPTIONS settings indicate
that lazy deallocation has the potential to worsen throughput dramatically.
Performance degradation occurs when multiple threads try to clear the lazy
free cache simultaneously. Various experiments to avoid this bottleneck
failed to completely solve this problem, while adding yet more complexity.
Bruce for putting lots of effort into these; getting them right isn't
easy, and they went through many iterations.
Submitted by: Steve Kargl <sgk@apl.washington.edu> with revisions from bde
is a violation of RFC 1034 [STD 13], it is accepted by certain name servers
as well as other popular operating systems' resolver library.
Bugs are mine.
Obtained from: ume
MFC after: 2 weeks
of disk names, where you must free each pointer, as well as the array
by hand. [1]
- Destaticize "disks" in Disk_Names, it has no reasons to be static.
PR: kern/96077 [1]
PR: kern/114110 [1]
MFC after: 1 month
Approved by: rwatson (mentor)
|x| or |y| and b is |y| or |x|) when mixing NaN arg(s).
hypot*() had its own foot shooting for mixing NaNs -- it swaps the
args so that |x| in bits is largest, but does this before quieting
signaling NaNs, so on amd64 (where the result of adding NaNs depends
on the order) it gets inconsistent results if setting the quiet bit
makes a difference, just like a similar ia64 and i387 hardware comparison.
The usual fix (see e_powf.c 1.13 for more details) of mixing using
(a+0.0)+-(b+0.0) doesn't work on amd64 if the args are swapped (since
the rder makes a difference with SSE). Fortunately, the original args
are unchanged and don't need to be swapped when we let the hardware
decide the mixing after quieting them, but we need to take their
absolute value.
hypotf() doesn't seem to have any real bugs masked by this non-bug.
On amd64, its maximum error in 2^32 trials on amd64 is now 0.8422 ulps,
and on i386 the maximum error is unchanged and about the same, except
with certain CFLAGS it magically drops to 0.5 (perfect rounding).
Convert to __FBSDID().
be into 12+24 bits of precision for extra-precision multiplication,
but was into 13+24 bits. On i386 with -O1 the bug was hidden by
accidental extra precision, but on amd64, in 2^32 trials the bug
caused about 200000 errors of more than 1 ulp, with a maximum error
of about 80 ulps. Now the maximum error in 2^32 trials on amd64
is 0.8573 ulps. It is still 0.8316 ulps on i386 with -O1.
The nearby decomposition of 1/ln2 and the decomposition of 2/(3ln2) in
the double precision version seem to be sub-optimal but not broken.
This uses 2 tricks to improve consistency so that more serious problems
aren't hidden in simple regression tests by noise for the NaNs:
- for a signaling NaN, adding 0.0 generates the invalid exception and
converts to a quiet NaN, and doesn't have too many effects for other
types of args (it converts -0 to +0 in some rounding modes, but that
hopefully doesn't change the result after adding the NaN arg). This
avoids some inconsistencies on i386 and ia64. On these arches, the
result of an operation on 2 NaNs is apparently the largest or the
smallest of the NaNs as bits (consistently largest or smallest for
each arch, but the opposite). I forget which way the comparison
goes and if the sign bit affects it. The quiet bit is is handled
poorly by not always setting it before the comparision or ignoring
it. Thus if one of the args was originally a signaling NaN and the
other was originally a quiet NaN, then the result depends too much
on whether the signaling NaN has been quieted at this point, which
in turn depends on optimizations and promotions. E.g., passing float
signaling NaNs to double functions must quiet them on conversion;
on i387, loading a signaling NaN of type float or double (but not
long double) into a register involves a conversion, so it quiets
signaling NaNs, so if the addition has 2 register operands than it
only sees quiet NaNs, but if the addition has a memory operand then
it sees a signaling NaN iff it is in the memory operand.
- subtraction instead of addition is used to avoid a dubious optimization
in old versions of gcc. For SSE operations, mixing of NaNs apparently
always gives the target operand. This is not as good as the i387
and ia64 behaviour. It doesn't mix NaNs at all, and makes addition
not quite commutative. Old versions of gcc sometimes rewrite x+y
to y+x and thus give different results (in bits) for NaNs. gcc-3.3.3
rewrites x+y to y+x for one of pow() and powf() but not the other,
so starting from float NaN args x and y, powf(x, y) was almost always
different from pow(x, y).
These tricks won't give consistency of 2-arg float and double functions
with long double ones on amd64, since long double ones use the i387
which has different semantics from SSE.
Convert to __FBSDID().
and trunc() to the corresponding long double functions. This is not
just an optimization for these arches. The full long double functions
have a wrong value for `huge', and the arches without full long doubles
depended on it being wrong.
This has the side effect of confusing gcc-4.2.1's optimizer into more
often doing the right thing. When it does the wrong thing here, it
seems to be mainly making too many copies of x with dependency chains.
This effect is tiny on amd64, but in some cases on i386 it is enormous.
E.g., on i386 (A64) with -O1, the current version of exp2() should
take about 50 cycles, but took 83 cycles before this change and 66
cycles after this change. exp2f() with -O1 only speeded up from 51
to 47 cycles. (exp2f() should take about 40 cycles, on an Athlon in
either i386 or amd64 mode, and now takes 42 on amd64). exp2l() with
-O1 slowed down from 155 cycles to 123 for some args; this is unimportant
since the i386 exp2l() is a fake; the wrong thing for it seems to
involve branch misprediction.
faster on all machines tested (old Celeron (P2), A64 (amd64 and i386)
and ia64) except on ia64 when compiled with -O1. It takes 2 more
multiplications, so it will be slower on old machines. The speedup
is about 8 cycles = 17% on A64 (amd64 and i386) with best CFLAGS
and some parallelism in the caller.
Move the evaluation of 2**k up a bit so that it doesn't compete too
much with the new polynomial evaluation. Unlike the previous
optimization, this rearrangement cannot change the result, so compilers
and CPU schedulers can do it, but they don't do it quite right yet.
This saves a whole 1 or 2 cycles on A64.
when the result is +-0. IEEE754 requires (in all rounding modes) that
if the result is +-0 then its sign is the same as that of the first
arg, but in round-towards-minus-infinity mode an uncorrected implementation
detail always reversed the sign. (The detail is that x-x with x's
sign positive gives -0 in this mode only, but the algorithm assumed
that x-x always has positive sign for such x.)
remquo() and remquof() seem to need the same fix, but I cannot test them
yet.
Use long doubles when mixing NaN args. This trick improves consistency
of results on at least amd64, so that more serious problems like the
above aren't hidden in simple regression tests by noise for the NaNs.
On amd64, hardware remainder should be used since it is about 10 times
faster than software remainder and is already used for remquo(), but
it involves using the i387 even for floats and doubles, and the i387
does NaN mixing which is better than but inconsistent with SSE NaN mixing.
Software remainder() would probably have been inconsistent with
software remainderl() for the same reason if the latter existed.
Signaling NaNs cause further inconsistencies on at least ia64 and i386.
Use __FBSDID().
exp2(i/TBLSIZE) * p(z) instead of only for the final multiplication
and addition. This fixes the code to match the comment that the maximum
error is 0.5010 ulps (except on machines that evaluate float expressions
in extra precision, e.g., i386's, where the evaluation was already
in extra precision).
Fix and expand the comment about use of double precision.
The relative roundoff error from evaluating p(z) in non-extra precision
was about 16 times larger than in exp2() because the interval length
is 16 times smaller. Its maximum was at least P1 * (1.0 ulps) *
max(|z|) ~= log(2) * 1.0 * 1/32 ~= 0.0217 ulps (1.0 ulps from the
addition in (1 + P1*z) with a cancelation error when z ~= -1/32). The
actual final maximum was 0.5313 ulps, of which 0.0303 ulps must have
come from the additional roundoff error in p(z). I can't explain why
the additional roundoff error was almost 3/2 times larger than the rough
estimate.
precision. The new polynomial has degree 4 instead of 10, and a maximum
error of 2**-30.04 ulps instead of 2**-33.15. This doesn't affect the
final error significantly; the maximum error was and is about 0.5015
ulps on i386 -O1, and the number of cases with an error of > 0.5 ulps
is increased from 13851 to 14407.
Note that the error is only this close to 0.5 ulps due to excessive
extra precision caused by compiler bugs on i386. The extra precision
could be obtained intentionally, and is useful for keeping the error
of the hyperbolic float functions below 1 ulp, since these functions
are implemented using expm1f. My recent change for scaling by 2**k
had the unintentional side effect of retaining extra precision for
longer, so callers of expm1f see errors of more like 0.0015 ulps than
0.5015 ulps, and for the hyperbolic functions this reduces the maximum
error from nearly about 2 ulps to about 0.75 ulps.
This is about 10% faster on i386 (A64). expm1* is still very slow,
but now the float version is actually significantly faster. The
algorithm is very sophisticated but not very good except on machines
with fast division.
arena_dalloc_lazy_hard() was split out of arena_dalloc_lazy() in revision
1.162.
Reduce thundering herd problems in lazy deallocation by randomly varying
how many probes a thread does before taking the slow path.
assumptions about whether bits are set at various times. This makes
adding other flags safe.
Reorganize functions in order to inline i{m,c,p,s,re}alloc(). This
allows the entire fast-path call chains for malloc() and free() to be
inlined. [1]
Suggested by: [1] Stuart Parmenter <stuart@mozilla.com>
exponent bits of the reduced result, construct 2**k (hopefully in
parallel with the construction of the reduced result) and multiply by
it. This tends to be much faster if the construction of 2**k is
actually in parallel, and might be faster even with no parallelism
since adjustment of the exponent requires a read-modify-wrtite at an
unfortunate time for pipelines.
In some cases involving exp2* on amd64 (A64), this change saves about
40 cycles or 30%. I think it is inherently only about 12 cycles faster
in these cases and the rest of the speedup is from partly-accidentally
avoiding compiler pessimizations (the construction of 2**k is now
manually scheduled for good results, and -O2 doesn't always mess this
up). In most cases on amd64 (A64) and i386 (A64) the speedup is about
20 cycles. The worst case that I found is expf on ia64 where this
change is a pessimization of about 10 cycles or 5%. The manual
scheduling for plain exp[f] is harder and not as tuned.
Details specific to expm1*:
- the saving is closer to 12 cycles than to 40 for expm1* on i386 (A64).
For some reason it is much larger for negative args.
- also convert to __FBSDID().
exponent bits of the reduced result, construct 2**k (hopefully in
parallel with the construction of the reduced result) and multiply by
it. This tends to be much faster if the construction of 2**k is
actually in parallel, and might be faster even with no parallelism
since adjustment of the exponent requires a read-modify-wrtite at an
unfortunate time for pipelines.
In some cases involving exp2* on amd64 (A64), this change saves about
40 cycles or 30%. I think it is inherently only about 12 cycles faster
in these cases and the rest of the speedup is from partly-accidentally
avoiding compiler pessimizations (the construction of 2**k is now
manually scheduled for good results, and -O2 doesn't always mess this
up). In most cases on amd64 (A64) and i386 (A64) the speedup is about
20 cycles. The worst case that I found is expf on ia64 where this
change is a pessimization of about 10 cycles or 5%. The manual
scheduling for plain exp[f] is harder and not as tuned.
This change ld128/s_exp2l.c has not been tested.
that is specialized for float precision. The new polynomial has degree
5 instead of 11, and a maximum error of 2**-27.74 ulps instead
of 2**-30.64. This doesn't affect the final error significantly; the
maximum error was and is about 0.9101 ulps on amd64 -01 and the number
of cases with an error of > 0.5 ulps is actually reduced by epsilon
despite the larger error in the polynomial.
This is about 15% faster on amd64 (A64), i386 (A64) and ia64. The asm
version is still used instead of this on i386 since it is faster and
more accurate.
threshold, according to the 'F' MALLOC_OPTIONS flag. This obsoletes the
'H' flag.
Try to realloc() large objects in place. This substantially speeds up
incremental large reallocations in the common case.
Fix a bug in arena_ralloc() that caused relocation of sub-page objects
even if the old and new sizes were in the same size class.
Maintain trees of runs and simplify the per-chunk page map. This allows
logarithmic-time searching for sufficiently large runs in
arena_run_alloc(), whereas the previous algorithm required linear time
in the worst case.
Break various large functions into smaller sub-functions, and inline
only the functions that are in the fast path for small object
allocation/deallocation.
Remove an unnecessary check in base_pages_alloc_mmap().
Avoid integer division in choose_arena() for the NO_TLS case on
single-CPU systems.
the semantics of pthread_mutex_islocked_np() to return true if and only if
the mutex is held by the current thread.
Obviously, change the regression test to match.
MFC after: 2 weeks
locked. This is intended primarily to support the userland equivalent
of the various *_ASSERT_LOCKED() macros we have in the kernel.
MFC after: 2 weeks
referencing the files VM pages are returned from the network stack,
making changes to the file safe.
This flag does not guarantee that the data has been transmitted to the
other end.
use. If it is in use, use the watched request, otherwise use the
lockuser's own request. Only allocate a lockuser request if both
requests are null.
PR: 119920
Tested by (6.x): Landon Fuller <landonf -at- bikemonkey -dot- org>
prerequisite for using this interface. However, the 'statinfo' struct
actually references CPUSTATES from <sys/resource.h>, so in fact it
requires <sys/resource.h> to compile. Use a nested include of
<sys/resource.h> to make the code match the docs.
Reported by: Pietro Cerutti gahr | gahr.ch
global header if nothing else has been written before the closing of
the archive. This will change the behaviour when creating archives
without members, i.e., instead of generating a 0-size archive file, an
archive with just the global header (8 bytes in total) will be created
and it is indeed a valid archive by the definition of libarchive, thus
subsequent operation on this archive will be accepted. This especially
solves the failure caused by following sequence: (several ports do)
% ar cru libfoo.a # without specifying obj files
% ranlib libfoo.a
Reviewed by: kientzle, jkoshy
Approved by: kientzle
Approved by: jkoshy (mentor)
Reported by: erwin
MFC after: 1 month
obey or ignore the size field on a hardlink entry. In particular,
if we're reading a non-POSIX archive, we should always ignore
the size field.
This should fix both the audio/xmcd port and the math/unixstat port.
Thanks to: Pav Lucistnik for pointing these two ports out to me.
MFC after: 7 days
fields in FTS and FTSENT structs being too narrow. In addition,
the narrow types creep from there into fts.c. As a result, fts(3)
consumers, e.g., find(1) or rm(1), can't handle file trees an ordinary
user can create, which can have security implications.
To fix the historic implementation of fts(3), OpenBSD and NetBSD
have already changed <fts.h> in somewhat incompatible ways, so we
are free to do so, too. This change is a superset of changes from
the other BSDs with a few more improvements. It doesn't touch
fts(3) functionality; it just extends integer types used by it to
match modern reality and the C standard.
Here are its points:
o For C object sizes, use size_t unless it's 100% certain that
the object will be really small. (Note that fts(3) can construct
pathnames _much_ longer than PATH_MAX for its consumers.)
o Avoid the short types because on modern platforms using them
results in larger and slower code. Change shorts to ints as
follows:
- For variables than count simple, limited things like states,
use plain vanilla `int' as it's the type of choice in C.
- For a limited number of bit flags use `unsigned' because signed
bit-wise operations are implementation-defined, i.e., unportable,
in C.
o For things that should be at least 64 bits wide, use long long
and not int64_t, as the latter is an optional type. See
FTSENT.fts_number aka FTS.fts_bignum. Extending fts_number `to
satisfy future needs' is pointless because there is fts_pointer,
which can be used to link to arbitrary data from an FTSENT.
However, there already are fts(3) consumers that require fts_number,
or fts_bignum, have at least 64 bits in it, so we must allow for them.
o For the tree depth, use `long'. This is a trade-off between making
this field too wide and allowing for 64-bit inode numbers and/or
chain-mounted filesystems. On the one hand, `long' is almost
enough for 32-bit filesystems on a 32-bit platform (our ino_t is
uint32_t now). On the other hand, platforms with a 64-bit (or
wider) `long' will be ready for 64-bit inode numbers, as well as
for several 32-bit filesystems mounted one under another. Note
that fts_level has to be signed because -1 is a magic value for it,
FTS_ROOTPARENTLEVEL.
o For the `nlinks' local var in fts_build(), use `long'. The logic
in fts_build() requires that `nlinks' be signed, but our nlink_t
currently is uint16_t. Therefore let's make the signed var wide
enough to be able to represent 2^16-1 in pure C99, and even 2^32-1
on a 64-bit platform. Perhaps the logic should be changed just
to use nlink_t, but it can be done later w/o breaking fts(3) ABI
any more because `nlinks' is just a local var.
This commit also inludes supporting stuff for the fts change:
o Preserve the old versions of fts(3) functions through libc symbol
versioning because the old versions appeared in all our former releases.
o Bump __FreeBSD_version just in case. There is a small chance that
some ill-written 3-rd party apps may fail to build or work correctly
if compiled after this change.
o Update the fts(3) manpage accordingly. In particular, remove
references to fts_bignum, which was a FreeBSD-specific hack to work
around the too narrow types of FTSENT members. Now fts_number is
at least 64 bits wide (long long) and fts_bignum is an undocumented
alias for fts_number kept around for compatibility reasons. According
to Google Code Search, the only big consumers of fts_bignum are in
our own source tree, so they can be fixed easily to use fts_number.
o Mention the change in src/UPDATING.
PR: bin/104458
Approved by: re (quite a while ago)
Discussed with: deischen (the symbol versioning part)
Reviewed by: -arch (mostly silence); das (generally OK, but we didn't
agree on some types used; assuming that no objections on
-arch let me to stick to my opinion)
Even though I believe this is a good change, it does
have the potential to break certain clients, so it's
good to document the reasoning behind the change.
cases which are used mainly by regression tests.
As usual, the cutoff for tiny args was not correctly translated to
float precision. It was 2**-54 but 2**-24 works. It must be about
2**-precision, since the error from approximating log(1+x) by x is
about the same as |x|. Exhaustive testing shows that 2**-24 gives
perfect rounding in round-to-nearest mode.
Similarly for the cutoff for being small, except this is not used by
so many other functions. It was 2**-29 but 2**-15 works. It must be
a bit smaller than sqrt(2**-precision), since the error from
approximating log(1+x) by x-x*x/2 is about the same as x*x. Exhaustive
testing shows that 2**-15 gives a maximum error of 0.5052 ulps in
round-to-nearest-mode. The algorithm for the general case is only good
for 0.8388 ulps, so this is sufficient (but it loses slightly on i386 --
then extra precision gives 0.5032 ulps for the general case).
While investigating this, I noticed that optimizing the usual case by
falling into a middle case involving a simple polynomial evaluation
(return x-x*x/2 instead of x here) is not such a good idea since it
gives an enormous pessimization of tinier args on machines for which
denormals are slow. Float x*x/2 is denormal when |x| ~< 2**-64 and
x*x/2 is evaluated in float precision, so it can easily be denormal
for normal x. This is even more interesting for general polynomial
evaluations. Multiplying out large powers of x is normally a good
optimization since it reduces dependencies, but it creates denormals
starting with quite large x.
forget to translate "float" to "double".
ucbtest didn't detect the bug, but exhaustive testing of the float
case relative to the double case eventually did. The bug only affects
args x with |x| ~> 2**19*(pi/2) on non-i386 (i386 is broken in a
different way for large args).
it should never have existed and it has not been used for many years
(floats are reduced faster using doubles). All relevant changes (just
the workaround for broken assignment) have been merged to the double
version.
there is a problem with non-floats (when i386 defaults to extra
precision). This essentially restores yesterday's behaviour for doubles
on i386 (since generic rint() isn't used and everywhere else assumed
working assignment), but for arches that use the generic rint() it
finishes restoring some of 1995's behaviour (don't waste time doing
unnecessary store/load).
variable hack for exp2f() only.
The volatile variable had a surprisingly large cost for exp2f() -- 19
cycles or 15% on i386 in the worst case observed. This is only partly
explained by there being several references to the variable, only one
of which benefited from it being volatile. Arches that have working
assignment are likely to benefit even more from not having any volatile
variable.
exp2() now has a chance of working with extra precision on i386.
exp2() has even more references to the variable, so it would have been
pessimized more by simply declaring the variable as volatile. Even
the temporary volatile variable for STRICT_ASSIGN costs 5-10% on i386,
(A64) so I will change STRICT_ASSIGN() to do an ordinary assignment
until i386 defaults to extra precision.
instead of a volatile cast hack for the float version only. The cast
hack broke with gcc-4, but this was harmless since the float version
hasn't been used for a few years. Merge from the float version so
that the double version has a chance of working on i386 with extra
precision.
See k_rem_pio2f.c rev.1.8 for the original hack.
Convert to _FBSDID().
hack for log1pf() only. The cast hack broke with gcc-4, resulting in
~1 million errors of more than 1 ulp, with a maximum error of ~1.5 ulps.
Now the maximum error for log1pf() on i386 is 0.5034 ulps again (this
depends on extra precision), and log1p() has a chance of working with
extra precision.
See s_log1pf.c 1.8 for the original hack. (It claims only 62343 large
errors).
Convert to _FBSDID(). Another thing broken with gcc-4 is the static
const hack used for rcsids.
around assignments not working for gcc on i386. Now volatile hacks
for rint() and rintf() don't needlessly pessimize so many arches
and the remaining pessimizations (for arm and powerpc) can be avoided
centrally.
This cleans up after s_rint.c 1.3 and 1.13 and s_rintf.c 1.3 and 1.9:
- s_rint.c 1.13 broke 1.3 by only using a volatile cast hack in 1 place
when it was needed in 2 places, and the volatile cast hack stopped
working with gcc-4. These bugs only affected correctness tests on
i386 since i386 normally uses asm rint() and doesn't support the
extra precision mode that would break assignments of doubles.
- s_rintf.c 1.9 improved(?) on 1.3 by using a volatile variable hack
instead of an extra-precision variable hack, but it declared 2
variables as volatile when only 1 variable needed to be volatile.
This only affected speed tests on i386 since i386 uses asm rintf().
long doubles (i386, amd64, ia64) and one for machines with 128-bit
long doubles (sparc64). Other platforms use the double version.
I've only done runtime testing on i386.
Thanks to bde@ for helpful discussions and bugfixes.
write a new test to exercise the hardlink strategies used
by different archive formats (tar, old cpio, new cpio).
This uncovered two problems, both fixed by this commit:
1) Enforce file size when writing files to disk.
2) When restoring hardlink entries, if they have data associated, go
ahead and open the file so we can write the data.
In particular, this fixes bsdtar/bsdcpio extraction of new cpio
formats where the "original" is empty and the subsequent "hardlink"
entry actually carries the data. It also provides correct behavior
for old cpio archives where hardlinked entries have their bodies
stored multiple times in the archive; the last body should always be
the one that ends up in the final file. The new pax format also
permits (but does not require) hardlinks to carry file data; again,
the last contents should always win.
Note that with any of these, a size of zero on a hardlink simply means
that the hardlink carries no data; it does not mean that the file has
zero size. A non-zero size on a hardlink does provide the file size.
Thanks to: John Baldwin, for reminding me about this long-standing bug
and sending me a simple example archive that prompted this test case
assignments and casts don't clip extra precision, if any. The
implementation is to assign to a temporary volatile variable and read
the result back to assign to the original lvalue.
lib/msun currently 2 different hard-coded hacks to avoid the problem
in just a few places and needs it in a few more places. One variant
uses volatile for the original lvalue. This works but is slower than
necessary. Another temporarily casts the lvalue to volatile. This
broke with gcc-4.2.1 or earlier (gcc now stores to the lvalue but
doesn't load from it).
instead of 32+32+15+1) on all arches that have such long doubles (amd64,
ia64 and i386). Large objects should be be accessed in large units,
and the 32+32+15+1[+padding] decomposition asks for almost the opposite
of that, sometimes resulting in very slow accesses depending on how
well the compiler ignores what we ask for and converts to the best
units for the given machine. E.g., on Athlons, there is a 10-20 cycle
penalty for accessing the middle 32-bit word immediately after an
80-bit store.
Whether actually using the alternative view is better is very machine-
dependent. A 32+32+16 view is probably best with old 32-bit systems
and gcc through 4.2.1. The compiler should mostly avoid the view and
generate best accesses, but gcc-4.2.1 is far from doing that. I think
64+16 is best for now. Similarly for doubles -- they should be using
64+0 especially on 64-bit machines, but fdlibm uses 32+32 extensively
for them. Fortunately, in 64-bit mode for doubles, gcc already ignores
the 32+32-bit view and generates best accesses in many cases.
one part" by simply ignoring the marker at the beginning
of the file. (Zip archivers reserve four bytes at the beginning
of each part of a multi-part archive, if it happens to only
require one part, those four bytes get filled with a placeholder
that can be ignored.)
Thanks to: Marius Nuennerich,
for pointing me to a Zip archive that libarchive couldn't handle
MFC after: 7 days
Specifically, remove the BUGS section and note that openpty(3) now always
does the various security-related steps. Also, update the error return
value section. The PR below is for the original bug rather than the doc
updates.
MFC after: 1 week
PR: bin/9770
into slowsort for some sequences because different parts of the
code used 'r' to store two different things, one of which was
signed. Clean things up by splitting 'r' into two variables, and
use a more meaningful name.
doesn't need to compensate for this situation.
While here, fix a minor longstanding bug that empty tar archives
(which begin with at least 512 zero bytes) never properly reported
their format. In particular, this fixes the output of:
bsdtar tvvf /dev/zero
And, of course, a new test to verify that libarchive correctly
recognizes the format of such files.
implement shm_open(2) and shm_unlink(2) in the kernel:
- Each shared memory file descriptor is associated with a swap-backed vm
object which provides the backing store. Each descriptor starts off with
a size of zero, but the size can be altered via ftruncate(2). The shared
memory file descriptors also support fstat(2). read(2), write(2),
ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared
memory file descriptors.
- shm_open(2) and shm_unlink(2) are now implemented as system calls that
manage shared memory file descriptors. The virtual namespace that maps
pathnames to shared memory file descriptors is implemented as a hash
table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash
of the pathname.
- As an extension, the constant 'SHM_ANON' may be specified in place of the
path argument to shm_open(2). In this case, an unnamed shared memory
file descriptor will be created similar to the IPC_PRIVATE key for
shmget(2). Note that the shared memory object can still be shared among
processes by sharing the file descriptor via fork(2) or sendmsg(2), but
it is unnamed. This effectively serves to implement the getmemfd() idea
bandied about the lists several times over the years.
- The backing store for shared memory file descriptors are garbage
collected when they are not referenced by any open file descriptors or
the shm_open(2) virtual namespace.
Submitted by: dillon, peter (previous versions)
Submitted by: rwatson (I based this on his version)
Reviewed by: alc (suggested converting getmemfd() to shm_open())
default. This has the disadvantage of rendering the datasize resource
limit irrelevant, but without this change, legitimate uses of more
memory than will fit in the data segment are thwarted by default.
Fix chunk_alloc_mmap() to work correctly if initial mapping is not
chunk-aligned and mapping extension fails.
the number of bytes read is actually not important as long as we have at
least what we ask for. Illustrate its benefits by using it throughout
the ZIP support code, except for the few cases where it doesn't apply.
Approved by: kientzle
exercises and verifies the libarchive APIs:
* Improved error reporting; hexdumps are now provided for
many file/memory content differences.
* Overall status more clearly counts "tests" and "assertions"
* Reference files can now be stored on disk instead of having
to be compiled into the test program itself. A couple of
tests have been converted to this more natural structure.
* Several memory leaks corrected so that leaks within libarchive
itself can be more easily detected and diagnosed.
* New test: GNU tar compatibility
* New test: Zip compatibility
* New test: Zero-byte writes to a compressed archive entry
* New test: archive_entry_strmode() format verification
* New test: mtree reader
* New test: write/read of large (2G - 1TB) entries to tar archives
(thanks to recent performance work, this test only requires a few seconds)
* New test: detailed format verification of cpio odc and newc writers
* Many minor additions/improvements to existing tests as well.
Clean up DSS-related locking and protect all pertinent variables with
dss_mtx (remove dss_chunks_mtx). This fixes race conditions that could
cause chunk leaks.
Reported by: [1] kris
This is a long-standing bug, but until recent changes it was difficult
to trigger, and even then its impact was non-catastrophic, with the
exception of revision 1.157.
Optimize chunk_alloc_mmap() to avoid the need for unmapping pages in the
common case. Thanks go to Kris Kennaway for a patch that inspired this
change.
Do not maintain a record of previously mmap'ed chunk address ranges.
The original intent was to avoid the extra system call overhead in
chunk_alloc_mmap(), which is no longer a concern. This also allows some
simplifications for the tree of unused DSS chunks.
Introduce huge_mtx and dss_chunks_mtx to replace chunks_mtx. There was
no compelling reason to use the same mutex for these disjoint purposes.
Avoid memset() for huge allocations when possible.
Maintain two trees instead of one for tracking unused DSS address
ranges. This allows scalable allocation of multi-chunk huge objects in
the DSS. Previously, multi-chunk huge allocation requests failed if the
DSS could not be extended.
that I've been working on but put off committing until after the
RELENG_7 branch, including:
* New manpages: cpio.5 mtree.5
* New archive_entry_strmode()
* New archive_entry_link_resolver()
* New read support: mtree format
* Internal API change: read format auction only runs once
* Running the auction only once allowed simplifying a lot of bid logic.
* Cpio robustness: search for next header after a sync error
* Support device nodes on ISO9660 images
* Eliminate a lot of unnecessary copies for uncompressed archives
* Corrected handling of new GNU --sparse --posix formats
* Correctly handle a zero-byte write to a compressed archive
* Fixed memory leaks
Many of these improvements were motivated by the upcoming bsdcpio
front-end.
There have also been extensive improvements to the libarchive_test
test harness, which I'll commit separately.
global list of all files.
- Mark kvm_getfiles() as broken since the live version exports struct xfile
with no filelist at the head and does so incorrectly and the deadfiles
version exports struct file with a filelist at the head. It is not known
if either version works or complies to the manpage.
order to support re-use of multi-chunk unused regions within the DSS for
huge allocations. This generalization is important to correct function
when mmap-based allocation is disabled.
Avoid zeroing re-used memory in the DSS unless it really needs to be
zeroed.
memory is acquired from the system via sbrk(2) and/or mmap(2). By default,
use sbrk(2) only, in order to support traditional use of resource limits.
Additionally, when both options are enabled, prefer the data segment to
anonymous mappings, in order to coexist better with large file mappings
in applications on 32-bit platforms. This change has the potential to
increase memory fragmentation due to the linear nature of the data
segment, but from a performance perspective this is mitigated by the use
of madvise(2). [1]
Add the ability to interpret integer prefixes in MALLOC_OPTIONS
processing. For example, MALLOC_OPTIONS=lllllllll can now be specified as
MALLOC_OPTIONS=9l.
Reported by: [1] rwatson
Design review: [1] alc, peter, rwatson
- Use PTY* for all pty(4) related constants.
- Use PTMX* for all pts(4) related constants.
- Consistently use _PATH_DEV PTMX rather than "/dev/ptmx".
- Revert 1.7 and properly fix it by using the correct prefix string for
pts(4) masters.
MFC after: 3 days
kick off any other users on the device line before using it since
openpty(3) is documented to do this. Note that grantpt(3) does not
call revoke(2), it only adjusts permissions and ownership.
MFC after: 3 days
my original implementation made both use the same code. Unfortunately,
this meant libm depended on a vendor header at compile time and previously-
unexposed vendor bits in libc at runtime.
Hence, I just wrote my own version of the relevant vendor routine. As it
turns out, mine has a factor of 8 fewer of lines of code, and is a bit more
readable anyway. The strtod() and *scanf() routines still use vendor code.
Reviewed by: bde
lynx, curl etc. Note that this patch differs significantly from that
in the PR, as the submitter refined it after submitting the PR.
PR: 110388
Submitted by: Alexander Pohoyda <alexander.pohoyda@gmx.net>
MFC after: 3 weeks
calculating run sizes. Use of the floating point unit was a potential
pessimization to context switching for applications that do not otherwise
use floating point math. [1]
Reformat cpp macro-related comments to improve consistency.
Submitted by: das
returned on a perfectly valid bzip2 stream whose decompressed size
is multiple of read-ahead buffer size. Reproduce the problem is easy:
create some power-of-two sized file (truncate -s 1m file will do),
bzip2 it and try to load it as md_image from loader. See how it fails.
The bug doesn't affect gzip code (which most of bzip2-reading code was
copied from) probably due to the fact that libgzip doesn't report
Z_STREAM_END with the last block, but requires extra call to inflate()
to retrieve it and has some extra data in the input stream at that time.
However, apply similar fix to gzipfs.c just in the case the API will
change in the future to do what bzip2 code does.
Add some ifdef'ed code to enable testing bzipfs.c from witin normal
FreeBSD environment as opposed to the restricted loader one, so that
one can use gdb and whatnot.
Sponsored by: Sippy Software, Inc., http://www.sippysoft.com/
MFC in: 7 days
someone thought it would be a good idea to copy z_abs() to libm in 1994.
However, it's never been declared or documented anywhere, and I'm
reasonably confident that nobody uses it.
Discussed with: bde, deischen, kan
I hope that this and the i386 version of it will not be needed, but
this is currently about 16 cycles or 36% faster than the C version,
and the i386 version is about 8 cycles or 19% faster than the C
version, due to poor optimization of the C version.
deallocation and dynamic load balancing via the MALLOC_LAZY_FREE and
MALLOC_BALANCE knobs. This is a non-functional change, since these
features are still enabled when possible.
Clean up a few things that more pedantic compiler settings would cause
complaints over.
adds two new directories in msun: ld80 and ld128. These are for
long double functions specific to the 80-bit long double format
used on x86-derived architectures, and the 128-bit format used on
sparc64, respectively.
loop count.
2. Add function pthread_mutex_setyieldloops_np to turn a mutex's yield
loop count.
3. Make environment variables PTHREAD_SPINLOOPS and PTHREAD_YIELDLOOPS
to be only used for turnning PTHREAD_MUTEX_ADAPTIVE_NP mutex.
default to the value of MK_KERBEROS unless set explicitly by
WITH_GSSAPI/WITHOUT_GSSAPI. (This introduces another type of
MK_* variables which itself is questionable.)
- Teach tools/build/options/makeman script that generates the
src.conf(5) manpage about the new type of MK_* variables.
- Fix broken logic in lib/Makefile.
when particular function can't be found in nsswitch-module. For
example, getgrouplist(3) will use module-supplied 'getgroupmembership'
function (which can work in an optimal way for such source as LDAP) and
will fall back to the stanard iterate-through-all-groups implementation
otherwise.
PR: ports/114655
Submitted by: Michael Hanselmann <freebsd AT hansmi DOT ch>
Reviewed by: brooks (mentor)
WITHOUT_KERBEROS knob. While GSS can be used for other things
some third party software (most notably ports/x11/kdelibs3)
takes the presence of libgssapi as an indication that kerberos
is available, and attempts to link with the kerberos libs. If
they are not available, the build will fail.
Because you might want to use GSS but not kerberos, add a knob
to re-enable it if WITHOUT_KERBEROS is present.
Document the new knob, and the new behavior of WITHOUT_KERBEROS.
Not objected and/or generally agreed to by: freebsd-arch
Problem discussed/analyzed in:
PR: ports/116484
is seems to be a problem for SUID applications, which we like to
prevent as much as possible.
PR: docs/39530
Submitted by: Soren Spies <sspies at apple dot com>
MFC After: 3 days
This protects against a race with an upcall in the parent during the
fork which can clobber the parent's tcb before the vm space is copied
in the child. The child then gets a corrupted tcb that is either null
or that points to another thread that doesn't exist in the child (after
a fork, only the fork()ing thread exists in the child).
Reported by: Arno J. Klaassen (arno at heho / snv / jussieu / fr)
a length field of zero; it does not mean the body is empty.
Thanks to: Lapo Luchini for sending me a JAR archive that demonstrated this bug
MFC after: 3 days
ia64, powerpc, and sparc64, use ANSI function headers and specifically
indicate the lack of arguments with 'void'. Otherwise, warnings are
generated at WARNS=3, leading to a compile failure with -Werror.
libkse in FreeBSD 8.0, do not build or install static versions of libkse
(i.e. libkse*.a) in the default case. Static versions will be built and
installed if libthr is not built or if libkse is the default threading
library.
Discussed on: freebsd-arch
MFC after: 3 days
contention. The intent is to dynamically adjust to load imbalances, which
can cause severe contention.
Use pthread mutexes where possible instead of libc "spinlocks" (they aren't
actually spin locks). Conceptually, this change is meant only to support
the dynamic load balancing code by enabling the use of spin locks, but it
has the added apparent benefit of substantially improving performance due to
reduced context switches when there is moderate arena lock contention.
Proper tuning parameter configuration for this change is a finicky business,
and it is very much machine-dependent. One seemingly promising solution
would be to run a tuning program during operating system installation that
computes appropriate settings for load balancing. (The pthreads adaptive
spin locks should probably be similarly tuned.)
vector of slots for lazily freed objects. For each deallocation, before
doing the hard work of locking the arena and deallocating, try several times
to randomly insert the object into the vector using atomic operations.
This approach is particularly effective at reducing contention for
multi-threaded applications that use the producer-consumer model, wherein
one producer thread allocates objects, then multiple consumer threads
deallocate those objects.
allocations. [1]
Fix calculation of the number of arenas when 'n' is specified via
MALLOC_OPTIONS.
Clean up various style inconsistencies.
Obtained from: [1] NetBSD
elf{32,64}_xlateto[fm]() translation functions. This change makes our
libelf compatible with other ELF(3) implementations. [1]
- Update manual page to reflect this change.
- Style fixes: wrap a long line.
Submitted by: jb [1]
