linux-kernel - Re: [PATCH] perf lock: track only specified threads

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: <4BE51A90.2060305@dcl.info.waseda.ac.jp>
Date:	Sat, 08 May 2010 17:02:24 +0900
From:	Hitoshi Mitake <mitake@....info.waseda.ac.jp>
To:	Frederic Weisbecker <fweisbec@...il.com>
CC:	linux-kernel@...r.kernel.org, h.mitake@...il.com,
	Ingo Molnar <mingo@...e.hu>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Jens Axboe <jens.axboe@...cle.com>,
	Jason Baron <jbaron@...hat.com>,
	Xiao Guangrong <xiaoguangrong@...fujitsu.com>
Subject: Re: [PATCH] perf lock: track only specified threads

On 05/07/10 09:49, Frederic Weisbecker wrote:
 > On Thu, May 06, 2010 at 06:32:56PM +0900, Hitoshi Mitake wrote:
 >> I implemented the feature of tracking only specified threads to perf 
lock.
 >> With -t option, users can specify which threads should be tracked.
 >>
 >> Example of usage:
 >> | % sudo ./perf lock info -t                    # info -t is 
convenient with this feature
 >> |  Thread ID: comm
 >> |          0: swapper
 >> |          1: init
 >> |         12: migration/3
 >> |         13: ksoftirqd/3
 >> |         27: events/0
 >> |         28: events/1
 >> |         29: events/2
 >> |         30: events/3
 >> |         31: events/4
 >> |        857: kondemand/0
 >> |        858: kondemand/1
 >> |        859: kondemand/2
 >> | ...
 >> | % sudo ./perf lock -t 27,28,29,30,31 report   # track only these 
threads
 >> |                 Name   acquired  contended total wait (ns)   max 
wait (ns)   min wait (ns)
 >
 >
 >
 > I'm not sure we want such per thread granularity filtering. I'm not
 > sure it will be very useful. But per process yeah.
 >
 > And actually we should do that on tracing time rather than on 
post-processing.
 > This will lower the tracing overhead a lot.
 >
 > Ideally I think we need:
 > 	./perf lock record ls -R /
 >
 > This would trace locks taken by this instance of ls only, ie: drop the -a
 > if we pass a command line.
 >
 > What do you think?
 >
 >

Ah, I completely agree with your opinion :)
Even if user wants to append "-a",
   ./perf lock record -a ls -R /
is enough. "-a" should not in default set of arguments.

I'll send the patch to drop "-a" later.

Thanks,
	Hitoshi
--
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/