From: David Ahern <dsahern@gmail.com>
To: Arnaldo Melo <acme@ghostprotocols.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
Mike Galbraith <efault@gmx.de>,
Namhyung Kim <namhyung@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH] perf session: Add option to copy events when queueing
Date: Fri, 25 Oct 2013 10:04:11 -0600 [thread overview]
Message-ID: <526A967B.6040008@gmail.com> (raw)
In-Reply-To: <20131024140731.GD6539@ghostprotocols.net>
On 10/24/13 8:07 AM, Arnaldo Melo wrote:
> What I thought was since we have to allocate memory _somewhere_ we could
> size the ring buffer in such a way that it would be big enough for us to
> leave those referenced entries there, not consumed, till we actually
> consume them when reordering the events, and if we run out of space, the
> kernel would just use LOST records, and not overwrite anything.
The tail pointer should only be moved up once all the events have been
flushed from the ordered samples queue. Right now the tail is moved up
when the event is read from the mmap (the patch in the other email
thread withstanding). The problem is that we do not have any linkage
between the event and the mmap that it came from; that information is
lost when the event is added to the ordered samples queue.
David
next prev parent reply other threads:[~2013-10-25 16:04 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-06 19:37 [PATCH] perf session: Add option to copy events when queueing David Ahern
2013-09-14 16:16 ` Frederic Weisbecker
2013-09-14 17:25 ` David Ahern
2013-09-16 16:40 ` Frederic Weisbecker
2013-09-17 4:14 ` David Ahern
2013-10-24 9:30 ` Frederic Weisbecker
2013-10-24 10:23 ` David Ahern
2013-10-24 12:27 ` Arnaldo Melo
2013-10-24 13:12 ` David Ahern
2013-10-24 14:07 ` Arnaldo Melo
2013-10-25 16:04 ` David Ahern [this message]
2013-10-02 12:18 ` Jiri Olsa
2013-10-02 12:38 ` Jiri Olsa
2013-10-02 12:52 ` David Ahern
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