rtla/osnoise: Better report when histogram is empty

When osnoise hist does not observe any samples above the threshold,
no entries are recorded and the final report shows empty entries
for the usual statistics (count, min, max, avg):

    [~]# osnoise hist -d 5s -T 500
    # RTLA osnoise histogram
    # Time unit is microseconds (us)
    # Duration:   0 00:00:05
    Index
    over:
    count:
    min:
    avg:
    max:

That could lead users to confusing interpretations of the results.

A simple solution is to report 0 for count and the statistics, making it
clear that no noise (above the defined threshold) was observed:

    [~]# osnoise hist -d 5s -T 500
    # RTLA osnoise histogram
    # Time unit is microseconds (us)
    # Duration:   0 00:00:05
    Index
    over: 0
    count: 0
    min: 0
    avg: 0
    max: 0

Link: https://lkml.kernel.org/r/Zml6JmH5cbS7-HfZ@uudg.org

Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Reviewed-by: John Kacur <jkacur@redhat.com>
Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
This commit is contained in:
Luis Claudio R. Goncalves 2024-06-12 07:36:22 -03:00 committed by Daniel Bristot de Oliveira
parent 59237b0c96
commit 587f05a88b

View File

@ -374,6 +374,7 @@ osnoise_print_stats(struct osnoise_hist_params *params, struct osnoise_tool *too
{
struct osnoise_hist_data *data = tool->data;
struct trace_instance *trace = &tool->trace;
int has_samples = 0;
int bucket, cpu;
int total;
@ -402,11 +403,25 @@ osnoise_print_stats(struct osnoise_hist_params *params, struct osnoise_tool *too
continue;
}
/* There are samples above the threshold */
has_samples = 1;
trace_seq_printf(trace->seq, "\n");
trace_seq_do_printf(trace->seq);
trace_seq_reset(trace->seq);
}
/*
* If no samples were recorded, skip calculations, print zeroed statistics
* and return.
*/
if (!has_samples) {
trace_seq_reset(trace->seq);
trace_seq_printf(trace->seq, "over: 0\ncount: 0\nmin: 0\navg: 0\nmax: 0\n");
trace_seq_do_printf(trace->seq);
trace_seq_reset(trace->seq);
return;
}
if (!params->no_index)
trace_seq_printf(trace->seq, "over: ");