linux-kernel - Re: [PATCH] sched: update_rq_clock() must skip ONE update

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] [day] [month] [year] [list]

Message-ID: <1396976162.4613.15.camel@marge.simpson.net>
Date:	Tue, 08 Apr 2014 18:56:02 +0200
From:	Mike Galbraith <umgwanakikbuti@...il.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Ingo Molnar <mingo@...nel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [PATCH] sched: update_rq_clock() must skip ONE update

On Tue, 2014-04-08 at 17:53 +0200, Peter Zijlstra wrote:

> OK; so as previously mentioned (Oct '13); I've entirely had it with
> skip_clock_update bugs, so I got angry and did the below.

Goody, kick butt take names ;-)

> Its not something I can merge, not least because it uses trace_printk(),
> but it should be usable to 1) demonstate the above actually helps and 2)
> make damn sure we got it right this time :-)

That would be nice, little cycle savers like this aren't supposed to
have nasty corner cases that can clean your clock (pun intended).

> I've not really stared at the output much yet; but when you select
> function_graph tracer; we get lovely things like:

I'll plug it into my quilt pile.

-Mike


--
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/