state where sleeping on a sleep queue is not allowed. The facility
doesn't support recursion but uses a simple private per-thread flag
(TDP_NOSLEEPING). The sleepq_add() function will panic if the flag is
set and INVARIANTS is enabled.
- Use this new facility to replace the g_xup and g_xdown mutexes that were
(ab)used to achieve similar behavior.
- Disallow sleeping in interrupt threads when invoking interrupt handlers.
MFC after: 1 week
Reviewed by: phk
the assumption that performance was more important that beancounter
quality statistics.
As it transpires the microoptimization is not measurable in the
real world and the inconsistent statistics confuse users, so revert
the decision.
MT6 candidate: possibly
MT5 candidate: possibly
in the g_up and g_down threads. Each time a bio is propelled up and
down the stack, an event is generating showing the provider, offset,
and length, as well as thread wakeup and work status information.
and bio_inbed fields to 0. Without this change we can end up with
I/O leakage in some rare situations.
I tested this change by putting failure probability mechanism simlar
to this used in NOP class into g_clone_bio(9) function, so it was
able to return NULL with the given probability.
Discussed with: phk
to warn about attempts to sleep in the I/O path. This change pushes the
definition and use of 'mymutex' behind #ifdef WITNESS to avoid the cost
in non-debugging cases. This results in a clear .22% performance win for
512 byte and 1k I/O tests on my SMP test box. Not much, but every bit
counts.
test is built to test GEOM as running in the kernel.
This commit is basically "unifdef -D_KERNEL" to remove the mainly #include
related code to support the userland-harness.
disk I/O processing.
The intent is that the disk driver in its hardware interrupt
routine will simply schedule the bio on the task queue with
a routine to finish off whatever needs done.
The g_up thread will then schedule this routine, the likely
outcome of which is a biodone() which queues the bio on
g_up's regular queue where it will be picked up and processed.
Compared to the using the regular taskqueue, this saves one
contextswitch.
Change our scheduling of the g_up and g_down queues to be water-tight,
at the cost of breaking the userland regression test-shims.
Input and ideas from: scottl
idle time.
Statistics now default to "on" and can be turned off with
sysctl kern.geom.collectstats=0
Performance impact of statistics collection is on the order of
800 nsec per consumer/provider set on a 700MHz Athlon.
Insted of embedding a struct g_stat in consumers and providers, merely
include a pointer.
Remove a couple of <sys/time.h> includes now unneeded.
Add a special allocator for struct g_stat. This allocator will allocate
entire pages and hand out g_stat functions from there. The "id" field
indicates free/used status.
Add "/dev/geom.stats" device driver whic exports the pages from the
allocator to userland with mmap(2) in read-only mode.
This mmap(2) interface should be considered a non-public interface and
the functions in libgeom (not yet committed) should be used to access
the statistics data.
