On Tue, Mar 19, 2019 at 5:56 PM Tzvetomir Stoyanov <tstoyanov@xxxxxxxxxx> wrote:
> +static unsigned long long timestamp_correct(unsigned long long ts,
> + struct tracecmd_input *handle)
> +{
> + int min, mid, max;
> +
> + if (handle->ts_offset)
> + return ts + handle->ts_offset;
> + if (!handle->ts_corr_count || !handle->ts_corr)
> + return ts;
> +
> + /* We have one sample, nothing to calc here */
> + if (handle->ts_corr_count == 1)
> + return ts + handle->ts_corr[0].offset;
> +
> + /* We have two samples, nothing to search here */
> + if (handle->ts_corr_count == 2)
> + return timestamp_correction_calc(ts, &handle->ts_corr[0],
> + &handle->ts_corr[1]);
> +
> + /* We have more than two samples */
> + min = 0;
> + max = handle->ts_corr_count-1;
> + mid = (min + max)/2;
> + while (min <= max) {
> + if (ts >= handle->ts_corr[mid].time &&
> + (mid == handle->ts_corr_count-1 ||
> + ts < handle->ts_corr[mid+1].time))
> + break;
> + if (ts < handle->ts_corr[mid].time) {
> + if (mid == 0)
> + break;
> + min = mid-1;
> + } else if (ts >= handle->ts_corr[mid+1].time)
> + max = mid + 1;
> + mid = (min + max)/2;
> + }
> +
> + if (mid >= handle->ts_corr_count-2)
> + return timestamp_correction_calc(ts, &handle->ts_corr[handle->ts_corr_count-2],
> + &handle->ts_corr[handle->ts_corr_count-1]);
> +
> + return timestamp_correction_calc(ts, &handle->ts_corr[mid],
> + &handle->ts_corr[mid+1]);
We can handle the edge cases first (ts is out of range) which would
simplify the search. Something like (untested):
if (ts <= handle->ts_corr[0]) {
return timestamp_correction_calc(ts,
&handle->ts_corr[0], &handle->ts_corr[1]);
} else if (ts >= handle->ts_corr[handle->ts_corr_count-1]) {
return timestamp_correction_calc(ts,
&handle->ts_corr[handle->ts_corr_count-2],
&handle->ts_corr[handle->ts_corr_count-1]);
}
min = 0;
max = handle->ts_corr_count-1;
mid = (min + max) / 2;
while (min <= max) {
if (ts < handle->ts_corr[mid].time)
min = mid - 1;
else if (ts > handle->ts_corr[mid].time)
max = mid + 1;
else
break;
mid = (min + max) / 2;
}
return timestamp_correction_calc(ts, &handle->ts_corr[mid],
&handle->ts_corr[mid+1]);
Too bad there's no lower_bound() in libc and bsearch() doesn't quite
cut it here.
> +}
> +
> /*
> * Page is mapped, now read in the page header info.
> */
> @@ -1049,7 +1116,7 @@ static int update_page_info(struct tracecmd_input *handle, int cpu)
> kbuffer_subbuffer_size(kbuf));
> return -1;
> }
> - handle->cpu_data[cpu].timestamp = kbuffer_timestamp(kbuf) + handle->ts_offset;
> + handle->cpu_data[cpu].timestamp = timestamp_correct(kbuffer_timestamp(kbuf), handle);
>
> if (handle->ts2secs)
> handle->cpu_data[cpu].timestamp *= handle->ts2secs;
> @@ -1776,7 +1843,7 @@ read_again:
> goto read_again;
> }
>
> - handle->cpu_data[cpu].timestamp = ts + handle->ts_offset;
> + handle->cpu_data[cpu].timestamp = timestamp_correct(ts, handle);
>
> if (handle->ts2secs) {
> handle->cpu_data[cpu].timestamp *= handle->ts2secs;
> @@ -2101,6 +2168,42 @@ void tracecmd_set_ts2secs(struct tracecmd_input *handle,
> handle->use_trace_clock = false;
> }
>
> +static int tsync_offset_cmp(const void *a, const void *b)
> +{
> + struct ts_offset_sample *ts_a = (struct ts_offset_sample *)a;
> + struct ts_offset_sample *ts_b = (struct ts_offset_sample *)b;
> +
> + if (ts_a->time > ts_b->time)
> + return 1;
> + if (ts_a->time < ts_b->time)
> + return -1;
> + return 0;
> +}
> +
> +static void tsync_offset_load(struct tracecmd_input *handle, char *buf)
> +{
> + int i, j;
> + long long *buf8 = (long long *)buf;
> +
> + for (i = 0; i < handle->ts_corr_count; i++) {
> + handle->ts_corr[i].time = tep_read_number(handle->pevent,
> + buf8+i, 8);
> + handle->ts_corr[i].offset = tep_read_number(handle->pevent,
> + buf8+handle->ts_corr_count+i, 8);
> + }
> + qsort(handle->ts_corr,
> + handle->ts_corr_count, sizeof(struct ts_offset_sample),
> + tsync_offset_cmp);
> + /* Filter possible samples with equal time */
> + for (i = 0, j = 0; i < handle->ts_corr_count; i++) {
> + if (i == 0 ||
> + handle->ts_corr[i].time != handle->ts_corr[i-1].time) {
> + handle->ts_corr[j++].time = handle->ts_corr[i].time;
> + handle->ts_corr[j++].offset = handle->ts_corr[i].offset;
`j` needs to be increment only once here. How about:
if (i == 0 || handle->ts_corr[i].time !=
handle->ts_corr[i-1].time)
handle->ts_corr[j++] = handle->ts_corr[i];
Thanks!
-- Slavi
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