From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751639AbeDTEhP (ORCPT ); Fri, 20 Apr 2018 00:37:15 -0400 Received: from mail-io0-f196.google.com ([209.85.223.196]:41494 "EHLO mail-io0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750729AbeDTEhO (ORCPT ); Fri, 20 Apr 2018 00:37:14 -0400 X-Google-Smtp-Source: AIpwx4/PDZ2ezfJTUzImgM/wVnP7iB48R0z2LFKVtumFZHg/ET6frMJXxhzaA3gB8m3IkmI+pqc4oGztE80ZK5ARS7g= MIME-Version: 1.0 In-Reply-To: References: <20180301163331.987775783@linutronix.de> <20180313063630.zxebyb7gczeiovyf@gmail.com> From: David Herrmann Date: Fri, 20 Apr 2018 06:37:12 +0200 Message-ID: Subject: Re: [RFC/RFT patch 0/7] timekeeping: Unify clock MONOTONIC and clock BOOTTIME To: John Stultz Cc: Ingo Molnar , Linus Torvalds , Thomas Gleixner , LKML , Peter Zijlstra , Steven Rostedt , Petr Mladek , Mark Salyzyn , Prarit Bhargava , Sergey Senozhatsky , Dmitry Torokhov , Kevin Easton , Michael Kerrisk , Jonathan Corbet Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hey On Tue, Mar 13, 2018 at 7:11 PM, John Stultz wrote: > On Mon, Mar 12, 2018 at 11:36 PM, Ingo Molnar wrote: >> Ok, I have edited all the changelogs accordingly (and also flipped around the >> 'clock MONOTONIC' language to the more readable 'the MONOTONIC clock' variant), >> the resulting titles are (in order): >> >> 72199320d49d: timekeeping: Add the new CLOCK_MONOTONIC_ACTIVE clock >> d6ed449afdb3: timekeeping: Make the MONOTONIC clock behave like the BOOTTIME clock >> f2d6fdbfd238: Input: Evdev - unify MONOTONIC and BOOTTIME clock behavior >> d6c7270e913d: timekeeping: Remove boot time specific code >> 7250a4047aa6: posix-timers: Unify MONOTONIC and BOOTTIME clock behavior >> 127bfa5f4342: hrtimer: Unify MONOTONIC and BOOTTIME clock behavior >> 92af4dcb4e1c: tracing: Unify the "boot" and "mono" tracing clocks >> >> I'll push these out after testing. > > I'm still anxious about userspace effects given how much I've seen the > current behavior documented, and wouldn't pushed for this myself (I'm > a worrier), but at least I'm not seeing any failures in initial > testing w/ kselftest so far. I get lots of timer-errors on Arch-Linux booting current master, after a suspend/resume cycle. Just a selection of errors I see on resume: systemd[1]: systemd-journald.service: Main process exited, code=dumped, status=6/ABRT rtkit-daemon[742]: The canary thread is apparently starving. Taking action. systemd[1]: systemd-udevd.service: Watchdog timeout (limit 3min)! systemd[1]: systemd-journald.service: Watchdog timeout (limit 3min)! kernel: e1000e 0000:00:1f.6: Failed to restore TIMINCA clock rate delta: -22 Lots of crashes with SIGABRT due to these. I did not bisect it, but it sounds related to me. Also, user-space uses CLOCK_MONOTONIC for watchdog timers. That is, a process is required to respond to a watchdog-request in a given MONOTONIC time-frame. If this jumps during suspend/resume, watchdogs will fire immediately. I don't see how this can work with the new MONOTONIC behavior? Thanks David