linux-kernel - Re: Reading perf counters at ftrace trace boundaries

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: <20130812014748.GP19750@two.firstfloor.org>
Date:	Mon, 12 Aug 2013 03:47:48 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Karim Yaghmour <karim.yaghmour@...rsys.com>
Cc:	Andi Kleen <andi@...stfloor.org>, linux-kernel@...r.kernel.org,
	Steven Rostedt <rostedt@...dmis.org>, mingo@...e.hu
Subject: Re: Reading perf counters at ftrace trace boundaries

> Indeed. It doesn't actually have to be at every single ftrace
> begin/exit. But possibly starting with some kind of every nth and then
> drilling down as the culprit is incrementally singled-out.

That's what normal sampling already does.

If you're worried about systematic shadow effects just randomize a bit.

-Andi
--
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/