linux-kernel - Re: [PATCH v2] perf tool: Fix ppid for synthesized fork events

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150326211146.GZ162412@redhat.com>
Date:	Thu, 26 Mar 2015 17:11:46 -0400
From:	Don Zickus <dzickus@...hat.com>
To:	David Ahern <dsahern@...il.com>
Cc:	acme@...nel.org, linux-kernel@...r.kernel.org,
	Joe Mario <jmario@...hat.com>, Jiri Olsa <jolsa@...hat.com>
Subject: Re: [PATCH v2] perf tool: Fix ppid for synthesized fork events

On Wed, Mar 25, 2015 at 01:55:44PM -0600, David Ahern wrote:
> >Hmm, I am not entirely sure this is correct.  You made an optimization that
> >hides the negative impact your patch does.  I would prefer you split this
> >patch into two pieces.  One with the read loop optimization (which I think
> >is great) and the second is your ppid change.
> >
> >I would then like to redo our test with the first patch applied and then
> >both patches applied.
> >
> 
> From your other response I take it you understand the patch now? It
> is a matter of semantics to break this single into 2 -- optimize the
> existing code and then add the ppid. End result will be what this
> patch shows. Before I do that can you /Joe confirm the performance
> is acceptable?

Hi David,

Sorry for drawing this out.  Originally the performance still seemed off.
But as we split the patch up to see where the perf impact was, the problem
seemed to have disappeared.  So we are testing the original patch again.

The only difference now is we were playing with the -BN option in perf based
on your changelog, just because we never used it before. :-)

One last test without the -BN option and if that looks fine, then we have no
objections.  Again sorry for dragging this out.  I will let you know
tomorrow EST.

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