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| author | jkim <jkim@FreeBSD.org> | 2011-04-12 23:49:07 +0000 |
|---|---|---|
| committer | jkim <jkim@FreeBSD.org> | 2011-04-12 23:49:07 +0000 |
| commit | 11b920013e4acebde8704db71b74a2e80405670c (patch) | |
| tree | cb041d4c6e6195b0da6712efd77550b3d7b2ef9a /sys/amd64 | |
| parent | 218c7113eda7be885de958c079152f70afe24ad9 (diff) | |
| download | FreeBSD-src-11b920013e4acebde8704db71b74a2e80405670c.zip FreeBSD-src-11b920013e4acebde8704db71b74a2e80405670c.tar.gz | |
Reduce errors in effective frequency calculation.
Diffstat (limited to 'sys/amd64')
| -rw-r--r-- | sys/amd64/amd64/machdep.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c index ace4cdf..127b2cf 100644 --- a/sys/amd64/amd64/machdep.c +++ b/sys/amd64/amd64/machdep.c @@ -546,7 +546,7 @@ int cpu_est_clockrate(int cpu_id, uint64_t *rate) { uint64_t tsc1, tsc2; - uint64_t acnt, mcnt; + uint64_t acnt, mcnt, perf; register_t reg; if (pcpu_find(cpu_id) == NULL || rate == NULL) @@ -579,7 +579,8 @@ cpu_est_clockrate(int cpu_id, uint64_t *rate) acnt = rdmsr(MSR_APERF); tsc2 = rdtsc(); intr_restore(reg); - *rate = (tsc2 - tsc1) / 1000 * acnt / mcnt * 1000000; + perf = 1000 * acnt / mcnt; + *rate = (tsc2 - tsc1) * perf; } else { tsc1 = rdtsc(); DELAY(1000); |
