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| author | Ingo Molnar <mingo@elte.hu> | 2009-05-13 12:54:01 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-05-15 09:46:56 +0200 |
| commit | f5a5a2f6e69e88647ae12da39f0ff3a510bcf0a6 (patch) | |
| tree | 85f7777f0b306fb553a3efc825b5337d301a8e34 /arch/x86/kernel | |
| parent | ec3232bdf8518bea8410f0027f870b24d3aa8753 (diff) | |
| download | op-kernel-dev-f5a5a2f6e69e88647ae12da39f0ff3a510bcf0a6.zip op-kernel-dev-f5a5a2f6e69e88647ae12da39f0ff3a510bcf0a6.tar.gz | |
perf_counter: x86: Fix throttling
If counters are disabled globally when a perfcounter IRQ/NMI hits,
and if we throttle in that case, we'll promote the '0' value to
the next lapic IRQ and disable all perfcounters at that point,
permanently ...
Fix it.
[ Impact: fix hung perfcounters under load ]
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_counter.c | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index 3a92a2b..88ae8ce 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -765,8 +765,13 @@ out: /* * Restore - do not reenable when global enable is off or throttled: */ - if (++cpuc->interrupts < PERFMON_MAX_INTERRUPTS) - intel_pmu_restore_all(cpuc->throttle_ctrl); + if (cpuc->throttle_ctrl) { + if (++cpuc->interrupts < PERFMON_MAX_INTERRUPTS) { + intel_pmu_restore_all(cpuc->throttle_ctrl); + } else { + pr_info("CPU#%d: perfcounters: max interrupt rate exceeded! Throttle on.\n", smp_processor_id()); + } + } return ret; } @@ -817,11 +822,16 @@ void perf_counter_unthrottle(void) cpuc = &__get_cpu_var(cpu_hw_counters); if (cpuc->interrupts >= PERFMON_MAX_INTERRUPTS) { - if (printk_ratelimit()) - printk(KERN_WARNING "perfcounters: max interrupts exceeded!\n"); + pr_info("CPU#%d: perfcounters: throttle off.\n", smp_processor_id()); + + /* + * Clear them before re-enabling irqs/NMIs again: + */ + cpuc->interrupts = 0; hw_perf_restore(cpuc->throttle_ctrl); + } else { + cpuc->interrupts = 0; } - cpuc->interrupts = 0; } void smp_perf_counter_interrupt(struct pt_regs *regs) |
