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rpm/rpm-4.4.2.3-no-rdtsc.patch

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commit c4d1ed354d8a3b1bc3352211f84ebb77a3ce8841
Author: Panu Matilainen <pmatilai@redhat.com>
Date: Mon Apr 21 12:39:18 2008 +0300
Rip i386-specific RDTSC support from rpmsw, use gettimeofday() everywhere
- we don't need accuracy beyond what gettimeofday() offers for bleeping
debugging benchmarks
- we especially don't need hw-specific magic asm voodoo to get unreliable
timing results (RDTSC isn't reliable with multi-core/hyperthreaded CPU's
etc etc)
- fixes rhbz#435309
diff --git a/rpmio/rpmsw.c b/rpmio/rpmsw.c
index 5334782..87a2311 100644
--- a/rpmio/rpmsw.c
+++ b/rpmio/rpmsw.c
@@ -22,78 +22,16 @@ static rpmtime_t rpmsw_overhead = 0;
static rpmtime_t rpmsw_cycles = 1;
/*@unchecked@*/
-static int rpmsw_type = 0;
-
-/*@unchecked@*/
static int rpmsw_initialized = 0;
-#if defined(__i386__)
-/* Swiped from glibc-2.3.2 sysdeps/i386/i686/hp-timing.h */
-
-#define HP_TIMING_ZERO(Var) (Var) = (0)
-#define HP_TIMING_NOW(Var) __asm__ __volatile__ ("rdtsc" : "=A" (Var))
-
-/* It's simple arithmetic for us. */
-#define HP_TIMING_DIFF(Diff, Start, End) (Diff) = ((End) - (Start))
-
-/* We have to jump through hoops to get this correctly implemented. */
-#define HP_TIMING_ACCUM(Sum, Diff) \
- do { \
- char __not_done; \
- hp_timing_t __oldval = (Sum); \
- hp_timing_t __diff = (Diff) - GL(dl_hp_timing_overhead); \
- do \
- { \
- hp_timing_t __newval = __oldval + __diff; \
- int __temp0, __temp1; \
- __asm__ __volatile__ ("xchgl %4, %%ebx\n\t" \
- "lock; cmpxchg8b %1\n\t" \
- "sete %0\n\t" \
- "movl %4, %%ebx" \
- : "=q" (__not_done), "=m" (Sum), \
- "=A" (__oldval), "=c" (__temp0), \
- "=SD" (__temp1) \
- : "1" (Sum), "2" (__oldval), \
- "3" (__newval >> 32), \
- "4" (__newval & 0xffffffff) \
- : "memory"); \
- } \
- while (__not_done); \
- } while (0)
-
-/* No threads, no extra work. */
-#define HP_TIMING_ACCUM_NT(Sum, Diff) (Sum) += (Diff)
-
-/* Print the time value. */
-#define HP_TIMING_PRINT(Buf, Len, Val) \
- do { \
- char __buf[20]; \
- char *__cp = _itoa (Val, __buf + sizeof (__buf), 10, 0); \
- int __len = (Len); \
- char *__dest = (Buf); \
- while (__len-- > 0 && __cp < __buf + sizeof (__buf)) \
- *__dest++ = *__cp++; \
- memcpy (__dest, " clock cycles", MIN (__len, sizeof (" clock cycles"))); \
- } while (0)
-#endif /* __i386__ */
-
rpmsw rpmswNow(rpmsw sw)
{
if (!rpmsw_initialized)
(void) rpmswInit();
if (sw == NULL)
return NULL;
- switch (rpmsw_type) {
- case 0:
- if (gettimeofday(&sw->u.tv, NULL))
- return NULL;
- break;
-#if defined(HP_TIMING_NOW)
- case 1:
- HP_TIMING_NOW(sw->u.ticks);
- break;
-#endif
- }
+ if (gettimeofday(&sw->u.tv, NULL))
+ return NULL;
return sw;
}
@@ -122,18 +60,7 @@ rpmtime_t rpmswDiff(rpmsw end, rpmsw begin)
if (end == NULL || begin == NULL)
return 0;
- switch (rpmsw_type) {
- default:
- case 0:
- ticks = tvsub(&end->u.tv, &begin->u.tv);
- break;
-#if defined(HP_TIMING_NOW)
- case 1:
- if (end->u.ticks > begin->u.ticks)
- HP_TIMING_DIFF(ticks, begin->u.ticks, end->u.ticks);
- break;
-#endif
- }
+ ticks = tvsub(&end->u.tv, &begin->u.tv);
if (ticks >= rpmsw_overhead)
ticks -= rpmsw_overhead;
if (rpmsw_cycles > 1)
@@ -141,38 +68,6 @@ rpmtime_t rpmswDiff(rpmsw end, rpmsw begin)
return ticks;
}
-#if defined(HP_TIMING_NOW)
-static rpmtime_t rpmswCalibrate(void)
- /*@globals internalState @*/
- /*@modifies internalState @*/
-{
- struct rpmsw_s begin, end;
- rpmtime_t ticks;
- struct timespec req, rem;
- int rc;
- int i;
-
-/*@-uniondef@*/
- (void) rpmswNow(&begin);
-/*@=uniondef@*/
- req.tv_sec = 0;
- req.tv_nsec = 20 * 1000 * 1000;
- for (i = 0; i < 100; i++) {
- rc = nanosleep(&req, &rem);
- if (rc == 0)
- break;
- if (rem.tv_sec == 0 && rem.tv_nsec == 0)
- break;
- req = rem; /* structure assignment */
- }
-/*@-uniondef@*/
- ticks = rpmswDiff(rpmswNow(&end), &begin);
-/*@=uniondef@*/
-
- return ticks;
-}
-#endif
-
rpmtime_t rpmswInit(void)
/*@globals rpmsw_cycles, rpmsw_initialized, rpmsw_overhead,
rpmsw_type @*/
@@ -180,8 +75,6 @@ rpmtime_t rpmswInit(void)
rpmsw_type @*/
{
struct rpmsw_s begin, end;
- unsigned long long sum_cycles = 0;
- rpmtime_t sum_usecs = 0;
rpmtime_t sum_overhead = 0;
rpmtime_t cycles;
int i;
@@ -193,38 +86,6 @@ rpmtime_t rpmswInit(void)
/* Convergence for simultaneous cycles and overhead is overkill ... */
for (i = 0; i < 3; i++) {
-#if defined(HP_TIMING_NOW)
- rpmtime_t save_cycles = rpmsw_cycles;
-
- /* We want cycles, not cycles/usec, here. */
- rpmsw_cycles = 1;
-
- /* Start wall clock. */
- rpmsw_type = 0;
-/*@-uniondef@*/
- (void) rpmswNow(&begin);
-/*@=uniondef@*/
-
- /* Get no. of cycles while doing nanosleep. */
- rpmsw_type = 1;
- cycles = rpmswCalibrate();
- if (save_cycles > 0 && rpmsw_overhead > 0)
- cycles -= (save_cycles * rpmsw_overhead);
- sum_cycles += cycles;
-
- /* Compute wall clock delta in usecs. */
- rpmsw_type = 0;
-/*@-uniondef@*/
- sum_usecs += rpmswDiff(rpmswNow(&end), &begin);
-/*@=uniondef@*/
- rpmsw_type = 1;
-
- /* Compute cycles/usec */
- rpmsw_cycles = sum_cycles/sum_usecs;
-#else
- rpmsw_type = 0;
-#endif
-
/* Calculate timing overhead in usecs. */
/*@-uniondef@*/
(void) rpmswNow(&begin);
@@ -232,7 +93,6 @@ rpmtime_t rpmswInit(void)
/*@=uniondef@*/
rpmsw_overhead = sum_overhead/(i+1);
-
}
return rpmsw_overhead;
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