linux-kernel - Re: [patch 10/10] Scheduler profiling

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: <20070706234315.GA19804@Krystal>
Date:	Fri, 6 Jul 2007 19:43:15 -0400
From:	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
To:	Adrian Bunk <bunk@...sta.de>
Cc:	Chuck Ebbert <cebbert@...hat.com>,
	Andi Kleen <andi@...stfloor.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Alexey Dobriyan <adobriyan@...il.com>,
	linux-kernel@...r.kernel.org, mbligh@...gle.com
Subject: Re: [patch 10/10] Scheduler profiling - Use immediate values

* Adrian Bunk (bunk@...sta.de) wrote:
> On Fri, Jul 06, 2007 at 06:14:10PM -0400, Chuck Ebbert wrote:
> > On 07/06/2007 07:44 AM, Andi Kleen wrote:
> > > I think the optimization is a good idea, although i dislike it
> > > that it is complicated for the dynamic markers. If it was just
> > > static it would be much simpler.
> > 
> > Another thing to consider is that there might be hundreds of these
> > probes/tracepoints active in an instrumented kernel. The overhead
> > adds up fast, so the gain may be worth all the pain.
> 
> Only if you want to squeeze the last bit of performance out of
> _debugging_ functionality.
> 
> You avoid all the pain if you simply don't use debugging functionality 
> on production systems.
> 

Adrian,

Please have a look at my markers posts, especially:

http://www.ussg.iu.edu/hypermail/linux/kernel/0707.0/0669.html

And also look into OLS 2007 proceedings for Martin Bligh's paper on
Debugging Google sized clusters. It basically makes the case for adding
functionnality to debug _user space_ problems on production systems that
can be turned on dynamically.

Mathieu

> cu
> Adrian
> 
> -- 
> 
>        "Is there not promise of rain?" Ling Tan asked suddenly out
>         of the darkness. There had been need of rain for many days.
>        "Only a promise," Lao Er said.
>                                        Pearl S. Buck - Dragon Seed
> 

-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
-
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/