diff options
| author | Len Brown <len.brown@intel.com> | 2012-06-13 21:31:46 -0400 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2012-07-19 22:26:33 -0400 |
| commit | c3ae331d1c2fe25edfbece73fda0bb312445b636 (patch) | |
| tree | f8b0073148c028820bca3d5a0629f094cb7e6f44 | |
| parent | c98d5d9444732a032bc55d1a496bfa8439da9199 (diff) | |
tools/power: turbostat: fix large c1% issue
Under some conditions, c1% was displayed as very large number,
much higher than 100%.
c1% is not measured, it is derived as "that, which is left over"
from other counters. However, the other counters are not collected
atomically, and so it is possible for c1% to be calaculagted as
a small negative number -- displayed as very large positive.
There was a check for mperf vs tsc for this already,
but it needed to also include the other counters
that are used to calculate c1.
Signed-off-by: Len Brown <len.brown@intel.com>
| -rw-r--r-- | tools/power/x86/turbostat/turbostat.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c index b815a12159b2..861d77190206 100644 --- a/tools/power/x86/turbostat/turbostat.c +++ b/tools/power/x86/turbostat/turbostat.c @@ -444,6 +444,9 @@ delta_core(struct core_data *new, struct core_data *old) old->c7 = new->c7 - old->c7; } +/* + * old = new - old + */ void delta_thread(struct thread_data *new, struct thread_data *old, struct core_data *core_delta) @@ -482,19 +485,20 @@ delta_thread(struct thread_data *new, struct thread_data *old, /* - * As mperf and tsc collection are not atomic, - * it is possible for mperf's non-halted cycles + * As counter collection is not atomic, + * it is possible for mperf's non-halted cycles + idle states * to exceed TSC's all cycles: show c1 = 0% in that case. */ - if (old->mperf > old->tsc) + if ((old->mperf + core_delta->c3 + core_delta->c6 + core_delta->c7) > old->tsc) old->c1 = 0; else { /* normal case, derive c1 */ old->c1 = old->tsc - old->mperf - core_delta->c3 - core_delta->c6 - core_delta->c7; } + if (old->mperf == 0) { - if (verbose) fprintf(stderr, "cpu%d MPERF 0!\n", old->cpu_id); + if (verbose > 1) fprintf(stderr, "cpu%d MPERF 0!\n", old->cpu_id); old->mperf = 1; /* divide by 0 protection */ } |