[lttng-dev] [PATCH lttng-tools 04/10] Fix: ust-consumer: flush empty packets on snapshot channel

[Jérémie Galarneau]

Merged, thanks!

Jérémie

On Wed, May 18, 2016 at 2:04 PM, Mathieu Desnoyers
<mathieu.desnoyers at efficios.com> wrote:
> Snapshot operation on a non-stopped stream should use a "final" flush to
> ensure empty packets are flushed, so we gather timestamps at the moment
> where the snapshot is taken. This is important for streams that have a
> low amount of activity, which might be on an empty packet when the
> snapshot is triggered.
>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> ---
>  src/common/ust-consumer/ust-consumer.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/src/common/ust-consumer/ust-consumer.c b/src/common/ust-consumer/ust-consumer.c
> index 91ffdce..c631904 100644
> --- a/src/common/ust-consumer/ust-consumer.c
> +++ b/src/common/ust-consumer/ust-consumer.c
> @@ -1111,7 +1111,13 @@ static int snapshot_channel(uint64_t key, char *path, uint64_t relayd_id,
>                         }
>                 }
>
> -               ustctl_flush_buffer(stream->ustream, 1);
> +               /*
> +                * If tracing is active, we want to perform a "full" buffer flush.
> +                * Else, if quiescent, it has already been done by the prior stop.
> +                */
> +               if (!stream->quiescent) {
> +                       ustctl_flush_buffer(stream->ustream, 0);
> +               }
>
>                 ret = lttng_ustconsumer_take_snapshot(stream);
>                 if (ret < 0) {
> --
> 2.1.4
>



-- 
Jérémie Galarneau
EfficiOS Inc.
http://www.efficios.com