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| author | Robert Richter <robert.richter@amd.com> | 2009-06-12 17:58:48 +0200 |
|---|---|---|
| committer | Robert Richter <robert.richter@amd.com> | 2009-06-12 17:58:48 +0200 |
| commit | 1241eb8f136bf3ea409f61590e7663465906d158 (patch) | |
| tree | c8384237f19bb1094d9c90825a74e28393b60d00 /arch/x86/kernel/tsc.c | |
| parent | 51563a0e5650d0d76539625388d72d62b34c726e (diff) | |
| parent | 940010c5a314a7bd9b498593bc6ba1718ac5aec5 (diff) | |
| download | linux-1241eb8f136bf3ea409f61590e7663465906d158.tar.gz linux-1241eb8f136bf3ea409f61590e7663465906d158.tar.bz2 linux-1241eb8f136bf3ea409f61590e7663465906d158.zip | |
Merge commit 'tip/perfcounters-for-linus' into oprofile/master
Conflicts:
arch/x86/oprofile/op_model_ppro.c
Signed-off-by: Robert Richter <robert.richter@amd.com>
Diffstat (limited to 'arch/x86/kernel/tsc.c')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index d57de05dc430..3e1c057e98fe 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -384,13 +384,13 @@ unsigned long native_calibrate_tsc(void) { u64 tsc1, tsc2, delta, ref1, ref2; unsigned long tsc_pit_min = ULONG_MAX, tsc_ref_min = ULONG_MAX; - unsigned long flags, latch, ms, fast_calibrate, tsc_khz; + unsigned long flags, latch, ms, fast_calibrate, hv_tsc_khz; int hpet = is_hpet_enabled(), i, loopmin; - tsc_khz = get_hypervisor_tsc_freq(); - if (tsc_khz) { + hv_tsc_khz = get_hypervisor_tsc_freq(); + if (hv_tsc_khz) { printk(KERN_INFO "TSC: Frequency read from the hypervisor\n"); - return tsc_khz; + return hv_tsc_khz; } local_irq_save(flags); @@ -710,7 +710,16 @@ static cycle_t read_tsc(struct clocksource *cs) #ifdef CONFIG_X86_64 static cycle_t __vsyscall_fn vread_tsc(void) { - cycle_t ret = (cycle_t)vget_cycles(); + cycle_t ret; + + /* + * Surround the RDTSC by barriers, to make sure it's not + * speculated to outside the seqlock critical section and + * does not cause time warps: + */ + rdtsc_barrier(); + ret = (cycle_t)vget_cycles(); + rdtsc_barrier(); return ret >= __vsyscall_gtod_data.clock.cycle_last ? ret : __vsyscall_gtod_data.clock.cycle_last; |