diff options
| author | Jan Beulich <jbeulich@novell.com> | 2006-05-30 16:47:54 -0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-05-30 23:31:05 -0400 |
| commit | b2468e525f29882f866cb0b832956e69328f9647 (patch) | |
| tree | 7a48afb9933732c6fccb2baa1e928e3508a3c940 /arch | |
| parent | 2ba567cbd7626700b800d4ce9503bd3cd78ed7ef (diff) | |
[PATCH] x86_64: fix last_tsc calculation of PM timer
From: "Jan Beulich" <jbeulich@novell.com>
The PM timer code updates vxtime.last_tsc, but this update was done
incorrectly in two ways:
- offset_delay being in microseconds requires multiplying with cpu_mhz
rather than cpu_khz
- the multiplication of offset_delay and cpu_khz (both being 32-bit
values) on most current CPUs would overflow (observed value of the
delay was approximately 4000us, yielding an overflow for frequencies
starting a little above 1GHz)
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86_64/kernel/pmtimer.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86_64/kernel/pmtimer.c b/arch/x86_64/kernel/pmtimer.c index b0444a415bd6..bf421ed26808 100644 --- a/arch/x86_64/kernel/pmtimer.c +++ b/arch/x86_64/kernel/pmtimer.c | |||
| @@ -68,7 +68,7 @@ int pmtimer_mark_offset(void) | |||
| 68 | offset_delay = delta % (USEC_PER_SEC / HZ); | 68 | offset_delay = delta % (USEC_PER_SEC / HZ); |
| 69 | 69 | ||
| 70 | rdtscll(tsc); | 70 | rdtscll(tsc); |
| 71 | vxtime.last_tsc = tsc - offset_delay * cpu_khz; | 71 | vxtime.last_tsc = tsc - offset_delay * (u64)cpu_khz / 1000; |
| 72 | 72 | ||
| 73 | /* don't calculate delay for first run, | 73 | /* don't calculate delay for first run, |
| 74 | or if we've got less then a tick */ | 74 | or if we've got less then a tick */ |