From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Baron Subject: [LSF/MM TOPIC] epoll topics Date: Thu, 15 Jan 2015 23:08:37 -0500 Message-ID: <54B88EC5.9020904@akamai.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: "linux-fsdevel@vger.kernel.org" , famz@redhat.com, normalperson@yhbt.net To: lsf-pc@lists.linux-foundation.org Return-path: Received: from prod-mail-xrelay07.akamai.com ([72.246.2.115]:37559 "EHLO prod-mail-xrelay07.akamai.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752983AbbAPEIj (ORCPT ); Thu, 15 Jan 2015 23:08:39 -0500 Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Hi, I think it would be interesting to discuss recent topics that have come up around epoll. I recently proposed a new locking scheme that removes the global locking using 'connected components', see: https://lkml.org/lkml/2015/1/15/667. There is a new syscall to batch epoll_ctl() operations and improve the timer precision that Fam Zheng is proposing: https://lkml.org/lkml/2015/1/8/70. In addition, Eric Wong has proposed a scheme using 'wait free queues' to improve lock contention between wakeups and event gathering: https://lkml.org/lkml/2013/3/14/14. In addition, we've observed some short comings from our production systems. Because wait queues are woken up in order, we can get unfair loading across threads, and we can also receive unecessary wakeups. It would be great to discuss these topics further. Thanks, -Jason