Re: [PATCH] cyclictest histogram overflow instance tracking

[John Kacur <jkacur@redhat.com>]

Ok, I'm in the process of gathering up patches - and I'll pass the to Clark.

Thanks

John

----- Original Message -----
> On 10/15/12 09:38, Bhavesh Davda wrote:
> > Hello Frank,
> > 
> > Friendly ping, to make sure this doesn't fall through the cracks.
> 
> You need to ping Clark Williams or John Kacur (not sure which...).
> 
> > 
> > Thanks
> > 
> > - Bhavesh
> > 
> > On Oct 11, 2012, at 1:59 PM, Bhavesh Davda wrote:
> > 
> >> Thanks for the review, Frank.
> >>
> >> On Oct 11, 2012, at 12:57 PM, Frank Rowand wrote:
> >>> Nice idea…
> >> Thanks
> >>
> >>> Suggest:
> >>>       printf("# Histogram Overflows at cycle number:");
> >>>
> >> Done
> >>
> >>>> - 		printf(" %05lu", par[j]->stats->hist_overflow);
> >>>> +		printf(" %05lu", par[j]->stats->hist_overflow);
> >>>
> >>> Am I blind, or is that a whitespace change?  (The latest version
> >>> I have does not seem
> >>> to have any white space issues in that line.)
> >>>
> >> Turns out I had removed extraneous whitespace. My vim settings
> >> allow me to see extraneous whitespaces in red, so I get annoyed
> >> by them and can fix them up. So I've removed a few more in the
> >> revised diffs (sorry!)
> >>
> >>> Suggest:
> >>>
> >>> +             printf("# thread %d:", j);
> >>>
> >> Done
> >>
> >>> Nit: You don't need stats->outliers_overflow.  You can calculate
> >>> it from
> >>> stats->hist_overflow - stats->num_outliers:
> >>>
> >> Nice catch! I've removed outliers_overflow now.
> >>
> >>
> >> From: Bhavesh Davda <bhavesh@vmware.com>
> >>
> >> Add feature to cyclictest histogram mode to track cycle counts
> >> every time a
> >> sample overflows the histogram limit. This should help identify if
> >> there is a
> >> timing pattern to jitters in cyclictest runs.
> >>
> >> Example output (with -h 10):
> >>  ...
> >>  Histogram Overflows: 00000 00253 00000 00005 00000 00024 00003
> >>  00005
> >>  Histogram Overflow at cycle number:
> >>  Thread 0:
> >>  Thread 1: 00023 00028 00337 00338 00339 00340 00341 00342 00343
> >>  00344 # 00243 others
> >>  Thread 2:
> >>  Thread 3: 10486 10487 10488 10489 10490
> >>  Thread 4:
> >>  Thread 5: 00002 00004 00008 00012 00178 10458 10459 10460 10461
> >>  10462 # 00014 others
> >>  Thread 6: 05954 08954 29955
> >>  Thread 7: 20536 20537 20538 20539 20540
> >>  ...
> >>
> >> Signed-off-by: Bhavesh Davda <bhavesh@vmware.com>
> >> ---
> >> src/cyclictest/cyclictest.c |   38
> >> +++++++++++++++++++++++++++++---------
> >> 1 files changed, 29 insertions(+), 9 deletions(-)
> >>
> >> diff --git a/src/cyclictest/cyclictest.c
> >> b/src/cyclictest/cyclictest.c
> >> index 731b4bd..dc985de 100644
> >> --- a/src/cyclictest/cyclictest.c
> >> +++ b/src/cyclictest/cyclictest.c
> >> @@ -147,6 +147,7 @@ struct thread_stat {
> >> 	double avg;
> >> 	long *values;
> >> 	long *hist_array;
> >> +        unsigned long *outliers;
> >> 	pthread_t thread;
> >> 	int threadstarted;
> >> 	int tid;
> >> @@ -154,6 +155,7 @@ struct thread_stat {
> >> 	long redmax;
> >> 	long cycleofmax;
> >> 	long hist_overflow;
> >> +        long num_outliers;
> >> };
> >>
> >> static int shutdown;
> >> @@ -756,8 +758,11 @@ void *timerthread(void *param)
> >>
> >> 		/* Update the histogram */
> >> 		if (histogram) {
> >> -			if (diff >= histogram)
> >> +			if (diff >= histogram) {
> >> 				stat->hist_overflow++;
> >> +				if (stat->num_outliers < histogram)
> >> +					stat->outliers[stat->num_outliers++] = stat->cycles - 1;
> >> +			}
> >> 			else
> >> 				stat->hist_array[diff]++;
> >> 		}
> >> @@ -811,7 +816,7 @@ static void display_help(int error)
> >> 		if (kernvar(O_RDONLY, "available_tracers", tracers,
> >> 		sizeof(tracers)))
> >> 			strcpy(tracers, "none");
> >> 	}
> >> -
> >> +
> >> 	printf("cyclictest V %1.2f\n", VERSION_STRING);
> >> 	printf("Usage:\n"
> >> 	       "cyclictest <options>\n\n"
> >> @@ -1188,7 +1193,7 @@ static int check_kernel(void)
> >> 		kv = KV_30;
> >> 		strcpy(functiontracer, "function");
> >> 		strcpy(traceroptions, "trace_options");
> >> -
> >> +
> >> 	} else
> >> 		kv = KV_NOT_SUPPORTED;
> >>
> >> @@ -1226,7 +1231,7 @@ static void print_tids(struct thread_param
> >> *par[], int nthreads)
> >>
> >> static void print_hist(struct thread_param *par[], int nthreads)
> >> {
> >> -	int i, j;
> >> +	int i, j, k;
> >> 	unsigned long long int log_entries[nthreads+1];
> >> 	unsigned long maxmax, alloverflows;
> >>
> >> @@ -1270,7 +1275,7 @@ static void print_hist(struct thread_param
> >> *par[], int nthreads)
> >> 	printf("# Max Latencies:");
> >> 	maxmax = 0;
> >> 	for (j = 0; j < nthreads; j++) {
> >> - 		printf(" %05lu", par[j]->stats->max);
> >> +		printf(" %05lu", par[j]->stats->max);
> >> 		if (par[j]->stats->max > maxmax)
> >> 			maxmax = par[j]->stats->max;
> >> 	}
> >> @@ -1280,9 +1285,20 @@ static void print_hist(struct thread_param
> >> *par[], int nthreads)
> >> 	printf("# Histogram Overflows:");
> >> 	alloverflows = 0;
> >> 	for (j = 0; j < nthreads; j++) {
> >> - 		printf(" %05lu", par[j]->stats->hist_overflow);
> >> +		printf(" %05lu", par[j]->stats->hist_overflow);
> >> 		alloverflows += par[j]->stats->hist_overflow;
> >> 	}
> >> +	printf("\n");
> >> +	printf("# Histogram Overflow at cycle number:\n");
> >> +	for (j = 0; j < nthreads; j++) {
> >> +		printf("# Thread %d:", j);
> >> +		for (k = 0; k < par[j]->stats->num_outliers; k++)
> >> +			printf(" %05lu", par[j]->stats->outliers[k]);
> >> +		if (par[j]->stats->num_outliers < par[j]->stats->hist_overflow)
> >> +			printf(" # %05lu others", par[j]->stats->hist_overflow -
> >> par[j]->stats->num_outliers);
> >> +                printf("\n");
> >> +        }
> >> +
> >> 	if (histofall && nthreads > 1)
> >> 		printf(" %05lu", alloverflows);
> >> 	printf("\n");
> >> @@ -1434,10 +1450,12 @@ int main(int argc, char **argv)
> >> 			int bufsize = histogram * sizeof(long);
> >>
> >> 			stat->hist_array = threadalloc(bufsize, node);
> >> -			if (stat->hist_array == NULL)
> >> +			stat->outliers = threadalloc(bufsize, node);
> >> +			if (stat->hist_array == NULL || stat->outliers == NULL)
> >> 				fatal("failed to allocate histogram of size %d on node %d\n",
> >> 				      histogram, i);
> >> 			memset(stat->hist_array, 0, bufsize);
> >> +			memset(stat->outliers, 0, bufsize);
> >> 		}
> >>
> >> 		if (verbose) {
> >> @@ -1553,8 +1571,10 @@ int main(int argc, char **argv)
> >>
> >> 	if (histogram) {
> >> 		print_hist(parameters, num_threads);
> >> -		for (i = 0; i < num_threads; i++)
> >> +		for (i = 0; i < num_threads; i++) {
> >> 			threadfree(statistics[i]->hist_array, histogram*sizeof(long),
> >> 			parameters[i]->node);
> >> +			threadfree(statistics[i]->outliers, histogram*sizeof(long),
> >> parameters[i]->node);
> >> +                }
> >> 	}
> >>
> >> 	if (tracelimit) {
> >> @@ -1564,7 +1584,7 @@ int main(int argc, char **argv)
> >> 			printf("# Break value: %lu\n", break_thread_value);
> >> 		}
> >> 	}
> >> -
> >> +
> >>
> >> 	for (i=0; i < num_threads; i++) {
> >> 		if (!statistics[i])
> >> --
> >> 1.7.1
> >>
> > 
> > --
> > Bhavesh Davda
> > bhavesh@vmware.com
> 
> 
> 
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