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authorPaul Mackerras <paulus@samba.org>2007-11-09 16:39:38 -0500
committerIngo Molnar <mingo@elte.hu>2007-11-09 16:39:38 -0500
commitfa13a5a1f25f671d084d8884be96fc48d9b68275 (patch)
tree97dae05bb5baef806a6dcbeed8b7eb5bdc61e4ae /arch/powerpc
parent9a41785cc43d88397f787a651ed7286a33f8462f (diff)
sched: restore deterministic CPU accounting on powerpc
Since powerpc started using CONFIG_GENERIC_CLOCKEVENTS, the deterministic CPU accounting (CONFIG_VIRT_CPU_ACCOUNTING) has been broken on powerpc, because we end up counting user time twice: once in timer_interrupt() and once in update_process_times(). This fixes the problem by pulling the code in update_process_times that updates utime and stime into a separate function called account_process_tick. If CONFIG_VIRT_CPU_ACCOUNTING is not defined, there is a version of account_process_tick in kernel/timer.c that simply accounts a whole tick to either utime or stime as before. If CONFIG_VIRT_CPU_ACCOUNTING is defined, then arch code gets to implement account_process_tick. This also lets us simplify the s390 code a bit; it means that the s390 timer interrupt can now call update_process_times even when CONFIG_VIRT_CPU_ACCOUNTING is turned on, and can just implement a suitable account_process_tick(). account_process_tick() now takes the task_struct * as an argument. Tested both with and without CONFIG_VIRT_CPU_ACCOUNTING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kernel/process.c2
-rw-r--r--arch/powerpc/kernel/time.c25
2 files changed, 2 insertions, 25 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index b9d88374f14f..41e13f4cc6e3 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -350,7 +350,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
350 local_irq_save(flags); 350 local_irq_save(flags);
351 351
352 account_system_vtime(current); 352 account_system_vtime(current);
353 account_process_vtime(current); 353 account_process_tick(current, 0);
354 calculate_steal_time(); 354 calculate_steal_time();
355 355
356 last = _switch(old_thread, new_thread); 356 last = _switch(old_thread, new_thread);
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 9eb3284deac4..a70dfb76d0a8 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -259,7 +259,7 @@ void account_system_vtime(struct task_struct *tsk)
259 * user and system time records. 259 * user and system time records.
260 * Must be called with interrupts disabled. 260 * Must be called with interrupts disabled.
261 */ 261 */
262void account_process_vtime(struct task_struct *tsk) 262void account_process_tick(struct task_struct *tsk, int user_tick)
263{ 263{
264 cputime_t utime, utimescaled; 264 cputime_t utime, utimescaled;
265 265
@@ -274,18 +274,6 @@ void account_process_vtime(struct task_struct *tsk)
274 account_user_time_scaled(tsk, utimescaled); 274 account_user_time_scaled(tsk, utimescaled);
275} 275}
276 276
277static void account_process_time(struct pt_regs *regs)
278{
279 int cpu = smp_processor_id();
280
281 account_process_vtime(current);
282 run_local_timers();
283 if (rcu_pending(cpu))
284 rcu_check_callbacks(cpu, user_mode(regs));
285 scheduler_tick();
286 run_posix_cpu_timers(current);
287}
288
289/* 277/*
290 * Stuff for accounting stolen time. 278 * Stuff for accounting stolen time.
291 */ 279 */
@@ -375,7 +363,6 @@ static void snapshot_purr(void)
375 363
376#else /* ! CONFIG_VIRT_CPU_ACCOUNTING */ 364#else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
377#define calc_cputime_factors() 365#define calc_cputime_factors()
378#define account_process_time(regs) update_process_times(user_mode(regs))
379#define calculate_steal_time() do { } while (0) 366#define calculate_steal_time() do { } while (0)
380#endif 367#endif
381 368
@@ -599,16 +586,6 @@ void timer_interrupt(struct pt_regs * regs)
599 get_lppaca()->int_dword.fields.decr_int = 0; 586 get_lppaca()->int_dword.fields.decr_int = 0;
600#endif 587#endif
601 588
602 /*
603 * We cannot disable the decrementer, so in the period
604 * between this cpu's being marked offline in cpu_online_map
605 * and calling stop-self, it is taking timer interrupts.
606 * Avoid calling into the scheduler rebalancing code if this
607 * is the case.
608 */
609 if (!cpu_is_offline(cpu))
610 account_process_time(regs);
611
612 if (evt->event_handler) 589 if (evt->event_handler)
613 evt->event_handler(evt); 590 evt->event_handler(evt);
614 else 591 else