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| author | Jan Beulich <jbeulich@novell.com> | 2006-05-30 22:47:54 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-05-30 20:31:05 -0700 |
| commit | b2468e525f29882f866cb0b832956e69328f9647 (patch) | |
| tree | 7a48afb9933732c6fccb2baa1e928e3508a3c940 /arch | |
| parent | 2ba567cbd7626700b800d4ce9503bd3cd78ed7ef (diff) | |
| download | linux-3.10-b2468e525f29882f866cb0b832956e69328f9647.tar.gz linux-3.10-b2468e525f29882f866cb0b832956e69328f9647.tar.bz2 linux-3.10-b2468e525f29882f866cb0b832956e69328f9647.zip | |
[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 b0444a415bd..bf421ed2680 100644 --- a/arch/x86_64/kernel/pmtimer.c +++ b/arch/x86_64/kernel/pmtimer.c @@ -68,7 +68,7 @@ int pmtimer_mark_offset(void) offset_delay = delta % (USEC_PER_SEC / HZ); rdtscll(tsc); - vxtime.last_tsc = tsc - offset_delay * cpu_khz; + vxtime.last_tsc = tsc - offset_delay * (u64)cpu_khz / 1000; /* don't calculate delay for first run, or if we've got less then a tick */ |