On Thu, 13 Sep 2018, Ralf Ramsauer wrote:
> If the histogram output is enabled, cyclictest dumps lines of all latencies,
> even if the specific latency was never hit. For analysing a histogram, it is
> sufficient to only dump latencies that actually occured. This patch skips
> latencies that were never hit with respect to all threads.
>
> If cyclictest is used in combination with --nsecs, this removes a lot of
> output noise.
>
> It shrinks output to:
> $ cyclictest --threads 2 --affinity 2-3 --priority 99 --histofall 100 --loops 100000
> # /dev/cpu_dma_latency set to 0us
> policy: fifo: loadavg: 0.03 0.13 0.07 1/560 1248
>
> T: 0 ( 1228) P:99 I:1000 C: 100000 Min: 2 Act: 2 Avg: 2 Max: 4
> T: 1 ( 1229) P:99 I:1000 C: 100000 Min: 2 Act: 2 Avg: 2 Max: 4
> # Histogram
> 000002 069425 067138 136563
> 000003 030536 032850 063386
> 000004 000039 000012 000051
> # Total: 000100000 000100000 000200000
> # Min Latencies: 00002 00002
> # Avg Latencies: 00002 00002
> # Max Latencies: 00004 00004 00004
> # Histogram Overflows: 00000 00000 00000
> # Histogram Overflow at cycle number:
> # Thread 0:
> # Thread 1:
>
> Signed-off-by: Ralf Ramsauer <ralf.ramsauer@xxxxxxxxxxxxxxxxx>
> ---
> src/cyclictest/cyclictest.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
> index 8d9ec80..0e8459c 100644
> --- a/src/cyclictest/cyclictest.c
> +++ b/src/cyclictest/cyclictest.c
> @@ -1988,16 +1988,23 @@ static void print_hist(struct thread_param *par[], int nthreads)
> fprintf(fd, "# Histogram\n");
> for (i = 0; i < histogram; i++) {
> unsigned long long int allthreads = 0;
> + unsigned long curr_latency = 0;
> +
> + for (j = 0; j < nthreads ; j++) {
> + curr_latency = par[j]->stats->hist_array[i];
> + allthreads += curr_latency;
> + log_entries[j] += curr_latency;
> + }
> + if (!allthreads)
> + continue;
>
> fprintf(fd, "%06d ", i);
>
> for (j = 0; j < nthreads; j++) {
> - unsigned long curr_latency=par[j]->stats->hist_array[i];
> + curr_latency = par[j]->stats->hist_array[i];
> fprintf(fd, "%06lu", curr_latency);
> if (j < nthreads - 1)
> fprintf(fd, "\t");
> - log_entries[j] += curr_latency;
> - allthreads += curr_latency;
> }
> if (histofall && nthreads > 1) {
> fprintf(fd, "\t%06llu", allthreads);
> --
> 2.19.0
>
>
Note, although I initially accepted this patch I may have to revert it.
The output of the histogram is not consumed just by humans but by
software, namely rteval
I am leaving the patch in for now and considering whether rteval could be
modified, but this is a heads-up.
The other option, is for this patch to be an option
Thanks
John
