linux-kernel - Re: sys_epoll_wait high CPU load in 2.6.37

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Message-ID: <1296057590.2899.73.camel@edumazet-laptop>
Date:	Wed, 26 Jan 2011 16:59:50 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Davide Libenzi <davidel@...ilserver.org>
Cc:	Simon Kirby <sim@...tway.ca>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Shawn Bohrer <shawn.bohrer@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: sys_epoll_wait high CPU load in 2.6.37

Le mercredi 26 janvier 2011 à 07:52 -0800, Davide Libenzi a écrit :

> For "above", I meant the current epoll expire time calculation, which was 
> described above in the message ;)

Well, problem was not an overflow, but doing a loop 2.000.000 times ;)

> The hint for a timespec_add_ms() was because we must be doing something 
> similar in poll, don't we (/me got no code in front ATM)?

Apparently its done differently in poll(), using
poll_select_set_timeout() helper.


Give me some minutes I'll try to cook an alternate patch


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