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 | 405e494d91bac85cc992f55ad434b0f325e399a5 (patch) | |
| tree | 2af37f5ad441730e7ebc0846d09a9402d21c3fc9 /arch/x86_64 | |
| parent | bf8696ed6dfa561198b4736deaf11ab68dcc4845 (diff) | |
[PATCH] x86-64: x86_64 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). This versions has 3 chunks compared to previous where
we had missed on check.
Changelog:
- make the x86-64 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>
Diffstat (limited to 'arch/x86_64')
| -rw-r--r-- | arch/x86_64/kernel/nmi.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c index dfab9f16736..010d3d9bd56 100644 --- a/arch/x86_64/kernel/nmi.c +++ b/arch/x86_64/kernel/nmi.c @@ -348,7 +348,7 @@ int __init check_nmi_watchdog (void) struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk); nmi_hz = 1; - if (wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR0) + if (wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR1) nmi_hz = adjust_for_32bit_ctr(nmi_hz); } @@ -713,8 +713,8 @@ 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; @@ -958,7 +958,7 @@ int __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason) /* start the cycle over again */ wrmsrl(wd->perfctr_msr, -((u64)cpu_khz * 1000 / nmi_hz)); - } else if (wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR0) { + } else if (wd->perfctr_msr == MSR_ARCH_PERFMON_PERFCTR1) { /* * ArchPerfom/Core Duo needs to re-unmask * the apic vector |