From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH 48/52] tools/power: turbostat: fix large c1% issue Date: Wed, 25 Jul 2012 09:03:14 -0400 Message-ID: <20120725130314.GB4783@phenom.dumpdata.com> References: <6af1c4fc5227af65092ebc848989693562bfa3e8.1343187617.git.len.brown@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Len Brown Cc: linux-acpi@vger.kernel.org, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Len Brown List-Id: linux-acpi@vger.kernel.org On Tue, Jul 24, 2012 at 11:41:44PM -0400, Len Brown wrote: > From: Len Brown > > 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 calculated. > 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 > --- > tools/power/x86/turbostat/turbostat.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c > index b815a12..861d771 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 */ > } > > -- > 1.7.12.rc0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html