dect
/
linux-2.6
Archived
13
0
Fork 0
Code Releases Activity

Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf: Fix throttle logic
  perf, x86: P4 PMU: Fix spurious NMI messages
This commit is contained in:
Linus Torvalds 2011-02-22 09:25:55 -08:00
parent 609b06f335 4fe757dd48
commit ee88347755
3 changed files with 24 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/include/asm/perf_event_p4.h
View File

@ -22,6 +22,7 @@
#define ARCH_P4_CNTRVAL_BITS (40)
#define ARCH_P4_CNTRVAL_MASK ((1ULL << ARCH_P4_CNTRVAL_BITS) - 1)
#define ARCH_P4_UNFLAGGED_BIT ((1ULL) << (ARCH_P4_CNTRVAL_BITS - 1))
#define P4_ESCR_EVENT_MASK 0x7e000000U
#define P4_ESCR_EVENT_SHIFT 25

11
arch/x86/kernel/cpu/perf_event_p4.c
View File

@ -770,9 +770,14 @@ static inline int p4_pmu_clear_cccr_ovf(struct hw_perf_event *hwc)
return 1;
}
/* it might be unflagged overflow */
rdmsrl(hwc->event_base + hwc->idx, v);
if (!(v & ARCH_P4_CNTRVAL_MASK))
/*
* In some circumstances the overflow might issue an NMI but did
* not set P4_CCCR_OVF bit. Because a counter holds a negative value
* we simply check for high bit being set, if it's cleared it means
* the counter has reached zero value and continued counting before
* real NMI signal was received:
*/
if (!(v & ARCH_P4_UNFLAGGED_BIT))
return 1;
return 0;

19
kernel/perf_event.c
View File

@ -782,6 +782,10 @@ retry:
raw_spin_unlock_irq(&ctx->lock);
}
#define MAX_INTERRUPTS (~0ULL)
static void perf_log_throttle(struct perf_event *event, int enable);
static int
event_sched_in(struct perf_event *event,
struct perf_cpu_context *cpuctx,
@ -794,6 +798,17 @@ event_sched_in(struct perf_event *event,
event->state = PERF_EVENT_STATE_ACTIVE;
event->oncpu = smp_processor_id();
/*
* Unthrottle events, since we scheduled we might have missed several
* ticks already, also for a heavily scheduling task there is little
* guarantee it'll get a tick in a timely manner.
*/
if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
perf_log_throttle(event, 1);
event->hw.interrupts = 0;
}
/*
* The new state must be visible before we turn it on in the hardware:
*/
@ -1596,10 +1611,6 @@ void __perf_event_task_sched_in(struct task_struct *task)
}
}
#define MAX_INTERRUPTS (~0ULL)
static void perf_log_throttle(struct perf_event *event, int enable);
static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
{
u64 frequency = event->attr.sample_freq;