@@ -142,7 +142,7 @@ config PPC
select ARCH_HAS_PHYS_TO_DMA
select ARCH_HAS_PMEM_API if PPC64
select ARCH_HAS_MEMBARRIER_CALLBACKS
- select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE
+ select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE && PPC64
select ARCH_HAS_SG_CHAIN
select ARCH_HAS_STRICT_KERNEL_RWX if ((PPC_BOOK3S_64 || PPC32) && !RELOCATABLE && !HIBERNATION)
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
@@ -15,8 +15,10 @@ struct cpu_accounting_data {
/* Accumulated cputime values to flush on ticks*/
unsigned long utime;
unsigned long stime;
+#ifdef ARCH_HAS_SCALED_CPUTIME
unsigned long utime_scaled;
unsigned long stime_scaled;
+#endif
unsigned long gtime;
unsigned long hardirq_time;
unsigned long softirq_time;
@@ -25,8 +27,10 @@ struct cpu_accounting_data {
/* Internal counters */
unsigned long starttime; /* TB value snapshot */
unsigned long starttime_user; /* TB value on exit to usermode */
+#ifdef ARCH_HAS_SCALED_CPUTIME
unsigned long startspurr; /* SPURR value snapshot */
unsigned long utime_sspurr; /* ->user_time when ->startspurr set */
+#endif
};
#endif
@@ -62,7 +62,9 @@ static inline void arch_vtime_task_switch(struct task_struct *prev)
struct cpu_accounting_data *acct0 = get_accounting(prev);
acct->starttime = acct0->starttime;
+#ifdef ARCH_HAS_SCALED_CPUTIME
acct->startspurr = acct0->startspurr;
+#endif
}
#endif
@@ -175,6 +175,7 @@ static void calc_cputime_factors(void)
* Read the SPURR on systems that have it, otherwise the PURR,
* or if that doesn't exist return the timebase value passed in.
*/
+#ifdef ARCH_HAS_SCALED_CPUTIME
static unsigned long read_spurr(unsigned long tb)
{
if (cpu_has_feature(CPU_FTR_SPURR))
@@ -183,6 +184,7 @@ static unsigned long read_spurr(unsigned long tb)
return mfspr(SPRN_PURR);
return tb;
}
+#endif
#ifdef CONFIG_PPC_SPLPAR
@@ -285,22 +287,28 @@ static unsigned long vtime_delta(struct task_struct *tsk,
unsigned long *stime_scaled,
unsigned long *steal_time)
{
- unsigned long now, nowscaled, deltascaled;
+ unsigned long now;
unsigned long stime;
+#ifdef ARCH_HAS_SCALED_CPUTIME
+ unsigned long nowscaled, deltascaled;
unsigned long utime, utime_scaled;
+#endif
struct cpu_accounting_data *acct = get_accounting(tsk);
WARN_ON_ONCE(!irqs_disabled());
now = mftb();
+#ifdef ARCH_HAS_SCALED_CPUTIME
nowscaled = read_spurr(now);
+#endif
stime = now - acct->starttime;
acct->starttime = now;
- deltascaled = nowscaled - acct->startspurr;
- acct->startspurr = nowscaled;
*steal_time = calculate_stolen_time(now);
+#ifdef ARCH_HAS_SCALED_CPUTIME
+ deltascaled = nowscaled - acct->startspurr;
+ acct->startspurr = nowscaled;
utime = acct->utime - acct->utime_sspurr;
acct->utime_sspurr = acct->utime;
@@ -325,6 +333,7 @@ static unsigned long vtime_delta(struct task_struct *tsk,
}
}
acct->utime_scaled += utime_scaled;
+#endif
return stime;
}
@@ -341,7 +350,9 @@ void vtime_account_system(struct task_struct *tsk)
if ((tsk->flags & PF_VCPU) && !irq_count()) {
acct->gtime += stime;
+#ifdef ARCH_HAS_SCALED_CPUTIME
acct->utime_scaled += stime_scaled;
+#endif
} else {
if (hardirq_count())
acct->hardirq_time += stime;
@@ -350,7 +361,9 @@ void vtime_account_system(struct task_struct *tsk)
else
acct->stime += stime;
+#ifdef ARCH_HAS_SCALED_CPUTIME
acct->stime_scaled += stime_scaled;
+#endif
}
}
EXPORT_SYMBOL_GPL(vtime_account_system);
@@ -378,8 +391,12 @@ void vtime_flush(struct task_struct *tsk)
if (acct->utime)
account_user_time(tsk, cputime_to_nsecs(acct->utime));
+#ifdef ARCH_HAS_SCALED_CPUTIME
if (acct->utime_scaled)
tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled);
+ if (acct->stime_scaled)
+ tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled);
+#endif
if (acct->gtime)
account_guest_time(tsk, cputime_to_nsecs(acct->gtime));
@@ -393,8 +410,6 @@ void vtime_flush(struct task_struct *tsk)
if (acct->stime)
account_system_index_time(tsk, cputime_to_nsecs(acct->stime),
CPUTIME_SYSTEM);
- if (acct->stime_scaled)
- tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled);
if (acct->hardirq_time)
account_system_index_time(tsk, cputime_to_nsecs(acct->hardirq_time),
@@ -404,13 +419,15 @@ void vtime_flush(struct task_struct *tsk)
CPUTIME_SOFTIRQ);
acct->utime = 0;
+#ifdef ARCH_HAS_SCALED_CPUTIME
acct->utime_scaled = 0;
acct->utime_sspurr = 0;
+ acct->stime_scaled = 0;
+#endif
acct->gtime = 0;
acct->steal_time = 0;
acct->idle_time = 0;
acct->stime = 0;
- acct->stime_scaled = 0;
acct->hardirq_time = 0;
acct->softirq_time = 0;
}
@@ -2439,11 +2439,15 @@ static void dump_one_paca(int cpu)
DUMP(p, accounting.utime, "%#-*lx");
DUMP(p, accounting.stime, "%#-*lx");
+#ifdef ARCH_HAS_SCALED_CPUTIME
DUMP(p, accounting.utime_scaled, "%#-*lx");
+#endif
DUMP(p, accounting.starttime, "%#-*lx");
DUMP(p, accounting.starttime_user, "%#-*lx");
+#ifdef ARCH_HAS_SCALED_CPUTIME
DUMP(p, accounting.startspurr, "%#-*lx");
DUMP(p, accounting.utime_sspurr, "%#-*lx");
+#endif
DUMP(p, accounting.steal_time, "%#-*lx");
#undef DUMP
scaled cputime is only meaningfull when the processor has SPURR and/or PURR, which means only on PPC64. Removing it on PPC32 significantly reduces the size of vtime_account_system() and vtime_account_idle() on an 8xx: Before: 00000114 l F .text 000000a8 vtime_delta 000004c0 g F .text 00000100 vtime_account_system 000005c0 g F .text 00000048 vtime_account_idle After: (vtime_delta gets inlined in the two functions) 00000418 g F .text 000000a0 vtime_account_system 000004b8 g F .text 00000054 vtime_account_idle In terms of performance, we also get approximatly 5% improvement on task switch: The following small benchmark app is run with perf stat: void *thread(void *arg) { int i; for (i = 0; i < atoi((char*)arg); i++) pthread_yield(); } int main(int argc, char **argv) { pthread_t th1, th2; pthread_create(&th1, NULL, thread, argv[1]); pthread_create(&th2, NULL, thread, argv[1]); pthread_join(th1, NULL); pthread_join(th2, NULL); return 0; } Before the patch: ~# perf stat chrt -f 98 ./sched 100000 Performance counter stats for 'chrt -f 98 ./sched 100000': 8622.166272 task-clock (msec) # 0.955 CPUs utilized 200027 context-switches # 0.023 M/sec After the patch: ~# perf stat chrt -f 98 ./sched 100000 Performance counter stats for 'chrt -f 98 ./sched 100000': 8207.090048 task-clock (msec) # 0.958 CPUs utilized 200025 context-switches # 0.024 M/sec Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- v3: Rebased following modifications in xmon.c v2: added ifdefs in xmon to fix compilation error arch/powerpc/Kconfig | 2 +- arch/powerpc/include/asm/accounting.h | 4 ++++ arch/powerpc/include/asm/cputime.h | 2 ++ arch/powerpc/kernel/time.c | 29 +++++++++++++++++++++++------ arch/powerpc/xmon/xmon.c | 4 ++++ 5 files changed, 34 insertions(+), 7 deletions(-)