From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751646AbcFWPXX (ORCPT ); Thu, 23 Jun 2016 11:23:23 -0400 Received: from www.linutronix.de ([62.245.132.108]:48296 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750799AbcFWPXW (ORCPT ); Thu, 23 Jun 2016 11:23:22 -0400 Date: Thu, 23 Jun 2016 17:21:14 +0200 (CEST) From: Thomas Gleixner To: Cyril Hrubis cc: George Spelvin , arjan@infradead.org, clm@fb.com, edumazet@google.com, fweisbec@gmail.com, lenb@kernel.org, linux-kernel@vger.kernel.org, ltp@lists.linux.it, mingo@kernel.org, paulmck@linux.vnet.ibm.com, peterz@infradead.org, riel@redhat.com, rt@linutronix.de, torvalds@linux-foundation.org, umgwanakikbuti@gmail.com Subject: Re: [LTP] [patch V2 00/20] timer: Refactor the timer wheel In-Reply-To: <20160623151127.GA20808@rei.lan> Message-ID: References: <20160623114759.GA19250@rei.lan> <20160623135803.636.qmail@ns.sciencehorizons.net> <20160623151127.GA20808@rei.lan> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 23 Jun 2016, Cyril Hrubis wrote: > > 1) sigtimedwait() is unusual in that it uses the jiffies timer. Most > > system call timeouts (including specifically the one in FUTEX_WAIT) > > use the high-resolution timer subsystem, which is a whole different > > animal with tighter guarantees, and > > That is likely POSIX conformance bug, since POSIX explicitly states that > sigtimedwait() shall use CLOCK_MONOTONIC to measure the timeout. > > "If the Monotonic Clock option is supported, the CLOCK_MONOTONIC clock > shall be used to measure the time interval specified by the timeout > argument." That's fine because jiffies is a less granular form of CLOCK_MONOTONIC. Thanks, tglx