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authorLen Brown <len.brown@intel.com>2012-06-13 21:31:46 -0400
committerLen Brown <len.brown@intel.com>2012-07-19 22:26:33 -0400
commitc3ae331d1c2fe25edfbece73fda0bb312445b636 (patch)
treef8b0073148c028820bca3d5a0629f094cb7e6f44 /tools/power
parentc98d5d9444732a032bc55d1a496bfa8439da9199 (diff)
downloadvexpress-lsk-c3ae331d1c2fe25edfbece73fda0bb312445b636.tar.gz
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>
Diffstat (limited to 'tools/power')
-rw-r--r--tools/power/x86/turbostat/turbostat.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index b815a12159b..861d7719020 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 */
}