linux-kernel - Re: [PATCH 0/7] perf, x86: Haswell LBR call stack support

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]

Date:	Wed, 26 Jun 2013 18:40:27 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	"Yan, Zheng" <zheng.z.yan@...el.com>, linux-kernel@...r.kernel.org,
	mingo@...nel.org, eranian@...gle.com, andi@...stfloor.org
Subject: Re: [PATCH 0/7] perf, x86: Haswell LBR call stack support

> So on pretty much every program you'd be lucky to get the top of the
> callstack but can end up with nearly nothing.

The last few entries up are usually the interesting ones, and those will
be preserved.

Do you really care about main() for profiling?

When you pop back up there may be a few situations where you
have a very small visible stack, but as soon as the program
starts nesting deeper again that will be fixed.

> Given that, and the other limitations I don't think its a fair
> replacement for user callchains.

It's not intended to be a full replacement, just to cover
cases that cannot give you callgraphs at all today.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only.
--
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/