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Date: Thu, 1 Mar 2007 10:54:02 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Pavel Machek <pavel@ucw.cz>, Theodore Tso <tytso@mit.edu>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Ulrich Drepper <drepper@redhat.com>, linux-kernel@vger.kernel.org,
       Arjan van de Ven <arjan@infradead.org>,
       Christoph Hellwig <hch@infradead.org>, Andrew Morton <akpm@zip.com.au>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>, Zach Brown <zach.brown@oracle.com>,
       "David S. Miller" <davem@davemloft.net>,
       Suparna Bhattacharya <suparna@in.ibm.com>,
       Davide Libenzi <davidel@xmailserver.org>,
       Jens Axboe <jens.axboe@oracle.com>,
       Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3
Message-ID: <20070301095402.GA14603@elte.hu>
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* Evgeniy Polyakov <johnpol@2ka.mipt.ru> wrote:

> I posted kevent/epoll benchmarks and related design issues too many 
> times both with handmade applications (which might be broken as hell) 
> and popular open-source servers to repeat them again.

numbers are crutial here - and given the epoll bugs in the evserver code 
that we found, do you have updated evserver benchmark results that 
compare epoll to kevent? I'm wondering why epoll has half the speed of 
kevent in those measurements - i suspect some possible benchmarking bug. 
The queueing model of epoll and kevent is roughly comparable, both do 
only a constant number of steps to serve one particular request, 
regardless of how many pending connections/requests there are. What is 
the CPU utilization of the server system during an epoll test, and what 
is the CPU utilization during a kevent test? 100% utilized in both 
cases?

	Ingo