diff options
| author | Stephane Eranian <eranian@hpl.hp.com> | 2007-05-02 19:27:05 +0200 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2007-05-02 19:27:05 +0200 |
| commit | bf8696ed6dfa561198b4736deaf11ab68dcc4845 (patch) | |
| tree | 54409e3dd141d468ab0f0c611ebb32f1d67af817 | |
| parent | 803d80f65038f77c4681a0d7708e9d693e68aaa8 (diff) | |
[PATCH] i386: i386 make NMI use PERFCTR1 for architectural perfmon (take 2)
Hello,
This patch against 2.6.20-git14 makes the NMI watchdog use PERFSEL1/PERFCTR1
instead of PERFSEL0/PERFCTR0 on processors supporting Intel architectural
perfmon, such as Intel Core 2. Although all PMU events can work on
both counters, the Precise Event-Based Sampling (PEBS) requires that the
event be in PERFCTR0 to work correctly (see section 18.14.4.1 in the
IA32 SDM Vol 3b).
A similar patch for x86-64 is to follow.
Changelog:
- make the i386 NMI watchdog use PERFSEL1/PERFCTR1 instead of PERFSEL0/PERFCTR0
on processors supporting the Intel architectural perfmon (e.g. Core 2 Duo).
This allows PEBS to work when the NMI watchdog is active.
signed-off-by: stephane eranian <eranian@hpl.hp.com>
Signed-off-by: Andi Kleen <ak@suse.de>
| -rw-r--r-- | arch/i386/kernel/nmi.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c index 84c3497efb6..aef22c881a0 100644 --- a/arch/i386/kernel/nmi.c +++ b/arch/i386/kernel/nmi.c @@ -365,7 +365,7 @@ static int __init check_nmi_watchdog(void) nmi_hz = 1; if (wd->perfctr_msr == MSR_P6_PERFCTR0 || - wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR0) { + wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR1) { nmi_hz = adjust_for_32bit_ctr(nmi_hz); } } @@ -799,8 +799,8 @@ static int setup_intel_arch_watchdog(void) (ebx & ARCH_PERFMON_UNHALTED_CORE_CYCLES_PRESENT)) goto fail; - perfctr_msr = MSR_ARCH_PERFMON_PERFCTR0; - evntsel_msr = MSR_ARCH_PERFMON_EVENTSEL0; + perfctr_msr = MSR_ARCH_PERFMON_PERFCTR1; + evntsel_msr = MSR_ARCH_PERFMON_EVENTSEL1; if (!__reserve_perfctr_nmi(-1, perfctr_msr)) goto fail; @@ -1080,7 +1080,7 @@ __kprobes int nmi_watchdog_tick(struct pt_regs * regs, unsigned reason) write_watchdog_counter(wd->perfctr_msr, NULL); } else if (wd->perfctr_msr == MSR_P6_PERFCTR0 || - wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR0) { + wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR1) { /* P6 based Pentium M need to re-unmask * the apic vector but it doesn't hurt * other P6 variant. |