From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753873AbbBQTdi (ORCPT ); Tue, 17 Feb 2015 14:33:38 -0500 Received: from prod-mail-xrelay02.akamai.com ([72.246.2.14]:36327 "EHLO prod-mail-xrelay02.akamai.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752044AbbBQTdh (ORCPT ); Tue, 17 Feb 2015 14:33:37 -0500 To: peterz@infradead.org, mingo@redhat.com, viro@zeniv.linux.org.uk Cc: akpm@linux-foundation.org, normalperson@yhbt.net, davidel@xmailserver.org, mtk.manpages@gmail.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org Message-Id: From: Jason Baron Subject: [PATCH v2 0/2] Add epoll round robin wakeup mode Date: Tue, 17 Feb 2015 19:33:36 +0000 (GMT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When we are sharing a wakeup source among multiple epoll fds, we end up with thundering herd wakeups, since there is currently no way to add to the wakeup source exclusively. This series introduces 2 new epoll flags, EPOLLEXCLUSIVE for adding to a wakeup source exclusively. And EPOLLROUNDROBIN which is to be used in conjunction to EPOLLEXCLUSIVE to evenly distribute the wakeups. This patch was originally motivated by a desire to improve wakeup balance and cpu usage for a listen socket() shared amongst multiple epoll fd sets. See: http://lwn.net/Articles/632590/ for previous test program and testing resutls. Epoll manpage text: EPOLLEXCLUSIVE Provides exclusive wakeups when attaching multiple epoll fds to a shared wakeup source. Must be specified with an EPOLL_CTL_ADD operation. EPOLLROUNDROBIN Provides balancing for exclusive wakeups when attaching multiple epoll fds to a shared wakeup soruce. Depends on EPOLLEXCLUSIVE being set and must be specified with an EPOLL_CTL_ADD operation. Thanks, -Jason Jason Baron (2): sched/wait: add round robin wakeup mode epoll: introduce EPOLLEXCLUSIVE and EPOLLROUNDROBIN fs/eventpoll.c | 25 ++++++++++++++++++++----- include/linux/wait.h | 11 +++++++++++ include/uapi/linux/eventpoll.h | 6 ++++++ kernel/sched/wait.c | 10 ++++++++-- 4 files changed, 45 insertions(+), 7 deletions(-) -- 1.8.2.rc2