linux-kernel - Re: [PATCH 1/2] timer: Avoid waking up an idle-core by migrate running timer

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: <1429653295.18561.16.camel@edumazet-glaptop2.roam.corp.google.com>
Date:	Tue, 21 Apr 2015 14:54:55 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	viresh kumar <viresh.kumar@...aro.org>,
	Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	linaro-kernel@...ts.linaro.org, linux-kernel@...r.kernel.org,
	Steven Miao <realmz6@...il.com>, shashim@...eaurora.org
Subject: Re: [PATCH 1/2] timer: Avoid waking up an idle-core by migrate
 running timer

On Tue, 2015-04-21 at 23:32 +0200, Thomas Gleixner wrote:

> 
> Are you realizing that __mod_timer() is a massive hotpath for network
> heavy workloads?

BTW I was considering using mod_timer_pinned() from these networking
timers (ie sk_reset_timer())

get_nohz_timer_target() sounds cool for laptop users, but is one cause
for bad responses to DDOS, when the selected cpu gets stressed.

This is the reason I used mod_timer_pinned() in commit 789f558cfb3680ae
("tcp/dccp: get rid of central timewait timer")



--
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/