From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Galbraith Subject: Re: [ANNOUNCE] 4.4-rc6-rt1 Date: Fri, 01 Jan 2016 08:19:41 +0100 Message-ID: <1451632781.9800.22.camel@gmail.com> References: <20151223225755.GA21121@linutronix.de> <20151231102441.581ce1e1@sluggy.hsv.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Thomas Gleixner , LKML , linux-rt-users , Steven Rostedt To: Clark Williams , Sebastian Andrzej Siewior Return-path: Received: from mail-wm0-f41.google.com ([74.125.82.41]:36797 "EHLO mail-wm0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751119AbcAAHTp (ORCPT ); Fri, 1 Jan 2016 02:19:45 -0500 In-Reply-To: <20151231102441.581ce1e1@sluggy.hsv.redhat.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Thu, 2015-12-31 at 10:24 -0600, Clark Williams wrote: > I pulled this update and tried it on my laptop (i7 quad-core with HT) > and an Atom testbox. I'm seeing a change in the cpu utilization of > ksoftirqd between 4.1.15-rt17 and 4.4-rc2-rt1, where the per-cpu > ksoftirqd threads are running at between 25-40% utilization: > > top - 10:15:57 up 13:46, 2 users, load average: 9.44, 9.30, 8.93 > Tasks: 188 total, 2 running, 186 sleeping, 0 stopped, 0 zombie > %Cpu(s): 4.7 us, 53.6 sy, 0.0 ni, 37.4 id, 0.1 wa, 0.0 hi, 4.2 si, 0.0 st > KiB Mem : 4046064 total, 480548 free, 179528 used, 3385988 buff/cache > KiB Swap: 5177340 total, 5169908 free, 7432 used. 3785624 avail Mem > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 3 root -2 0 0 0 0 S 37.3 0.0 307:52.44 ksoftirqd/0 > 32 root -2 0 0 0 0 S 37.3 0.0 308:08.72 ksoftirqd/2 > 42 root -2 0 0 0 0 R 37.3 0.0 308:32.84 ksoftirqd/3 > 22 root -2 0 0 0 0 S 26.9 0.0 222:29.82 ksoftirqd/1 > 1 root 20 0 46628 6980 4976 S 1.3 0.2 0:13.98 systemd > 22358 williams 20 0 159980 4552 3780 R 1.0 0.1 0:00.39 top Heh, I didn't notice immediately because I throttle nohz, am seeing only tiny utilization (but nohz idle isn't working). With throttle patch removed, box is screaming, expires=4294990471 pokes eyeball. swapper 0 [003] 392.708321: timer:hrtimer_cancel: hrtimer=0xffff88041ecce720 swapper 0 [003] 392.708321: timer:hrtimer_start: hrtimer=0xffff88041ecce720 function=tick_sched_timer/0x0 expires=4294990471 softexpires=4294990471 swapper 0 [003] 392.708323: timer:hrtimer_cancel: hrtimer=0xffff88041ecce720 swapper 0 [003] 392.708324: timer:hrtimer_expire_entry: hrtimer=0xffff88041ecce720 now=392697118535 function=tick_sched_timer/0x0 swapper 0 [003] 392.708325: timer:hrtimer_expire_exit: hrtimer=0xffff88041ecce720 swapper 0 [003] 392.708326: timer:hrtimer_start: hrtimer=0xffff88041ecce720 function=tick_sched_timer/0x0 expires=392700750000 softexpires=392700750000 swapper 0 [003] 392.708328: timer:tick_stop: success=yes msg= swapper 0 [003] 392.708329: timer:hrtimer_cancel: hrtimer=0xffff88041ecce720 swapper 0 [003] 392.708329: timer:hrtimer_start: hrtimer=0xffff88041ecce720 function=tick_sched_timer/0x0 expires=4294990471 softexpires=4294990471 swapper 0 [003] 392.708331: timer:hrtimer_cancel: hrtimer=0xffff88041ecce720 swapper 0 [003] 392.708332: timer:hrtimer_expire_entry: hrtimer=0xffff88041ecce720 now=392697126313 function=tick_sched_timer/0x0 swapper 0 [003] 392.708333: timer:hrtimer_expire_exit: hrtimer=0xffff88041ecce720 swapper 0 [003] 392.708334: timer:hrtimer_start: hrtimer=0xffff88041ecce720 function=tick_sched_timer/0x0 expires=392700750000 softexpires=392700750000 swapper 0 [003] 392.708336: timer:tick_stop: success=yes msg=