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perf, x86: Disable PEBS on clovertown chips 

This CPU has just too many handycaps to be really useful.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: paulus@samba.org
Cc: eranian@google.com
Cc: robert.richter@amd.com
Cc: fweisbec@gmail.com
LKML-Reference: <20100305154128.890278662@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2010-03-04 21:49:01 +01:00 committed by Ingo Molnar
parent 3adaebd695
commit 3c44780b22
2 changed files with 31 additions and 0 deletions
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4
arch/x86/kernel/cpu/perf_event.c
View File

@ -197,6 +197,7 @@ struct x86_pmu {
void (*put_event_constraints)(struct cpu_hw_events *cpuc,
struct perf_event *event);
struct event_constraint *event_constraints;
void (*quirks)(void);
void (*cpu_prepare)(int cpu);
void (*cpu_starting)(int cpu);
@ -1373,6 +1374,9 @@ void __init init_hw_perf_events(void)
pr_cont("%s PMU driver.\n", x86_pmu.name);
if (x86_pmu.quirks)
x86_pmu.quirks();
if (x86_pmu.num_events > X86_PMC_MAX_GENERIC) {
WARN(1, KERN_ERR "hw perf events %d > max(%d), clipping!",
x86_pmu.num_events, X86_PMC_MAX_GENERIC);

27
arch/x86/kernel/cpu/perf_event_intel.c
View File

@ -792,6 +792,32 @@ static __initconst struct x86_pmu intel_pmu = {
.cpu_dying = fini_debug_store_on_cpu,
};
static void intel_clovertown_quirks(void)
{
/*
* PEBS is unreliable due to:
*
* AJ67 - PEBS may experience CPL leaks
* AJ68 - PEBS PMI may be delayed by one event
* AJ69 - GLOBAL_STATUS[62] will only be set when DEBUGCTL[12]
* AJ106 - FREEZE_LBRS_ON_PMI doesn't work in combination with PEBS
*
* AJ67 could be worked around by restricting the OS/USR flags.
* AJ69 could be worked around by setting PMU_FREEZE_ON_PMI.
*
* AJ106 could possibly be worked around by not allowing LBR
* usage from PEBS, including the fixup.
* AJ68 could possibly be worked around by always programming
* a pebs_event_reset[0] value and coping with the lost events.
*
* But taken together it might just make sense to not enable PEBS on
* these chips.
*/
printk(KERN_WARNING "PEBS disabled due to CPU errata.\n");
x86_pmu.pebs = 0;
x86_pmu.pebs_constraints = NULL;
}
static __init int intel_pmu_init(void)
{
union cpuid10_edx edx;
@ -856,6 +882,7 @@ static __init int intel_pmu_init(void)
break;
case 15: /* original 65 nm celeron/pentium/core2/xeon, "Merom"/"Conroe" */
x86_pmu.quirks = intel_clovertown_quirks;
case 22: /* single-core 65 nm celeron/core2solo "Merom-L"/"Conroe-L" */
case 23: /* current 45 nm celeron/core2/xeon "Penryn"/"Wolfdale" */
case 29: /* six-core 45 nm xeon "Dunnington" */