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From: Johannes Berg <johannes@sipsolutions.net>
To: Steven Rostedt <rostedt@goodmis.org>,
	Tzvetomir Stoyanov <tstoyanov@vmware.com>
Cc: linux-trace-devel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] trace-cmd: Fix crash when trace-cmd is executed with args "profile -F sleep 1"
Date: Tue, 18 Jun 2019 19:54:05 +0200	[thread overview]
Message-ID: <5e7dc4f8b24431a0a6e417d64ed9c30d8cf19cb7.camel@sipsolutions.net> (raw)
In-Reply-To: <20190618122009.0998021e@gandalf.local.home>

On Tue, 2019-06-18 at 12:20 -0400, Steven Rostedt wrote:

> Heads up. Johannes found a regression that this code above causes
> reading a 1.7G file where the above code makes it go from reading it in
> 5 seconds, to over 2 minutes!

Actually, I didn't even let it finish ... It was something like 4.5
seconds to not finishing in 4.5 minutes, then I gave up. My prior
version was commit 1ad32c24746.

The file is 1.7G, but that's perhaps not the interesting part? A little
under 620k events - by my standards, that's a small file :-)

> I bisected it down to this commit (saw a small, but not so drastic
> performance issue it my tests). I asked Johannes to revert the commit,
> and he said that it removed the regression.

With that reverted I actually see ~2 seconds now, which is 2x faster
than before :-)

> He said he'll report this in the Bugzilla, but we should be looking at
> changing the realloc() logic.

https://bugzilla.kernel.org/show_bug.cgi?id=203927

johannes


      reply	other threads:[~2019-06-18 17:54 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-05 11:19 [PATCH v2 1/2] trace-cmd: Fix crash when trace-cmd is executed with args "profile -F sleep 1" Tzvetomir Stoyanov
2019-06-05 11:19 ` [PATCH v2 2/2] trace-cmd: Fix a possible race condition and deadlock in trace-cmd Tzvetomir Stoyanov
2019-06-07  6:48   ` Slavomir Kaslev
2019-06-18 16:20 ` [PATCH v2 1/2] trace-cmd: Fix crash when trace-cmd is executed with args "profile -F sleep 1" Steven Rostedt
2019-06-18 17:54   ` Johannes Berg [this message]

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