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Tune bytecode quitting

* src/bytecode.c (BYTE_CODE_QUIT): Check for GC, too.  Do the
check only once every 256 times.  This should be good enough, and
improves performance significantly on x86-64 as branch-prediction
typically assumes checking will not be done so the instruction
pipeline stays fuller.
(exec_byte_code): Set up the quit counter.  Don’t call maybe_gc
directly, as BYTE_CODE_QUIT does that now.
This commit is contained in:
Paul Eggert 2016-08-09 00:37:39 -07:00
parent 4d07064a43
commit d896f78973

View File

@ -368,6 +368,9 @@ relocate_byte_stack (void)
#define BYTE_CODE_QUIT \
do { \
if (quitcounter++) \
break; \
maybe_gc (); \
if (!NILP (Vquit_flag) && NILP (Vinhibit_quit)) \
{ \
Lisp_Object flag = Vquit_flag; \
@ -446,6 +449,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
stack.pc = stack.byte_string_start = SDATA (bytestr);
if (MAX_ALLOCA / word_size <= XFASTINT (maxdepth))
memory_full (SIZE_MAX);
unsigned char quitcounter = 0;
int stack_items = XFASTINT (maxdepth) + 1;
Lisp_Object *stack_base = alloca (stack_items * sizeof *top);
Lisp_Object *stack_lim = stack_base + stack_items;
@ -601,7 +605,6 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
CASE (Bgotoifnil):
{
Lisp_Object v1;
maybe_gc ();
op = FETCH2;
v1 = POP;
if (NILP (v1))
@ -788,7 +791,6 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
NEXT;
CASE (Bgoto):
maybe_gc ();
BYTE_CODE_QUIT;
op = FETCH2; /* pc = FETCH2 loses since FETCH2 contains pc++ */
CHECK_RANGE (op);
@ -798,7 +800,6 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
CASE (Bgotoifnonnil):
{
Lisp_Object v1;
maybe_gc ();
op = FETCH2;
v1 = POP;
if (!NILP (v1))
@ -811,7 +812,6 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
}
CASE (Bgotoifnilelsepop):
maybe_gc ();
op = FETCH2;
if (NILP (TOP))
{
@ -823,7 +823,6 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
NEXT;
CASE (Bgotoifnonnilelsepop):
maybe_gc ();
op = FETCH2;
if (!NILP (TOP))
{
@ -835,7 +834,6 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
NEXT;
CASE (BRgoto):
maybe_gc ();
BYTE_CODE_QUIT;
stack.pc += (int) *stack.pc - 127;
NEXT;
@ -843,7 +841,6 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
CASE (BRgotoifnil):
{
Lisp_Object v1;
maybe_gc ();
v1 = POP;
if (NILP (v1))
{
@ -857,7 +854,6 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
CASE (BRgotoifnonnil):
{
Lisp_Object v1;
maybe_gc ();
v1 = POP;
if (!NILP (v1))
{
@ -869,7 +865,6 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
}
CASE (BRgotoifnilelsepop):
maybe_gc ();
op = *stack.pc++;
if (NILP (TOP))
{
@ -880,7 +875,6 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
NEXT;
CASE (BRgotoifnonnilelsepop):
maybe_gc ();
op = *stack.pc++;
if (!NILP (TOP))
{