From: David Ahern <dsahern@gmail.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: acme@ghostprotocols.net, 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: Mon, 16 Sep 2013 22:14:08 -0600 [thread overview]
Message-ID: <5237D710.2020301@gmail.com> (raw)
In-Reply-To: <20130916164022.GA29373@localhost.localdomain>
On 9/16/13 10:40 AM, Frederic Weisbecker wrote:
>> Yes. I could make it the default behavior; just overhead in doing
>> that (malloc/copy for each event).
>
> Are there any tool that don't suffer from this bug somehow? If not then it must
> be applied unconditionally.
I believe only 'live' commands would be affected: top, kvm stat live, my
local scheduling daemon. perf-trace bypasses session and time ordering
(though I question that decision).
---8<---
>> size of event is determined by mmap_event (mmap2_event in latest
>> code) which is > 4096 because of the filename argument. Including
>> the event directly in sample_queue would balloon memory usage
>> (learned this the hard way!).
>
> Ah then perhaps we can allocate with the dynamic size of the event?
Yes, that's how I have it my patch -- allocate memory based on header
size and copy in the queue_event function. I think we agree on this part
now.
---8<---
>>> Although the mirrored os->sample_buffer condition check is a bit ugly and should move to
>>> a function. But the idea is there.
>>
>> Ok. That should be a separate patch. Are you going to submit that one?
>
> Yeah, unless you beat me at it :)
That's not going to happen on my end due to a recent time constraint
(jury duty - minimum 1 week trial). At best I can do a patch in early
October.
David
next prev parent reply other threads:[~2013-09-17 4:14 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 [this message]
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
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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