Re: tracepoint filter problems

From: Arnaldo Carvalho de Melo
Date: Mon Nov 02 2015 - 20:13:35 EST


Em Mon, Nov 02, 2015 at 10:50:51AM +0100, Peter Zijlstra escreveu:
> On Thu, Oct 29, 2015 at 12:27:42PM -0300, Arnaldo Carvalho de Melo wrote:
> > In the example below 'perf trace' will ask to see just the 'open' syscall, and
> > it works for the started workload, namely 'perf record', but then it'll call
> > 'sleep 100000000000' and there the filter doesn't apply, bummer :-\

> > The inherit bit is set, sure, as we can see when adding -vv to the 'perf trace'
> > call, ideas?

> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -6939,6 +6939,10 @@ static int perf_tp_filter_match(struct p
> {
> void *record = data->raw->data;
>
> + /* only top level events have filters set */
> + if (event->parent)
> + event = event->parent;
> +
> if (likely(!event->filter) || filter_match_preds(event->filter, record))
> return 1;
> return 0;

Thank you!

Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

[root@felicio ~]# trace -e bpf,nanosleep perf record -e /tmp/foo.o sleep 1
385.246 ( 0.062 ms): perf/13761 bpf(cmd: PROG_LOAD, uattr: 0x7ffd9900ac90, size: 48) = 3
1424.278 (999.497 ms): sleep/13762 nanosleep(rqtp: 0x7ffd4583a6e0 ) = 0
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.012 MB perf.data ]
[root@felicio ~]#

- Arnaldo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/