diff options
| author | Mathieu Poirier <mathieu.poirier@linaro.org> | 2019-04-26 13:59:37 -0600 |
|---|---|---|
| committer | Mathieu Poirier <mathieu.poirier@linaro.org> | 2019-05-03 09:35:28 -0600 |
| commit | 527c29fbd89f69c186d29280cae5279f5d1a494e (patch) | |
| tree | 2add1e9ab915b4b1b84f29b7f1f2d759be319d2a /drivers/hwtracing/coresight/coresight-tmc-etf.c | |
| parent | de0df8545a54fb9aa6c7e8d5f365d272399fa13d (diff) | |
coresight: perf: Don't set the truncated flag in snapshot mode
This patch avoids setting the truncated flag when operaring in snapshot
mode since the trace buffer is expected to be truncated and discontinuous
from one snapshot to another. Moreover when the truncated flag is set
the perf core stops enabling the event, waiting for user space to consume
the data. In snapshot mode this is clearly not what we want since it
results in stale data.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Diffstat (limited to 'drivers/hwtracing/coresight/coresight-tmc-etf.c')
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-tmc-etf.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c index d3025634f5e6..8039bd389034 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c @@ -538,7 +538,13 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev, lost = true; } - if (lost) + /* + * Don't set the TRUNCATED flag in snapshot mode because 1) the + * captured buffer is expected to be truncated and 2) a full buffer + * prevents the event from being re-enabled by the perf core, + * resulting in stale data being send to user space. + */ + if (!buf->snapshot && lost) perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); cur = buf->cur; |