Just an update: I am still encountering similar performance issues with the 4.9.0-1 kernel that was recently promoted to testing. In fact, the 4.9.0-1 kernel may be the worst yet in terms of this specific issue, with IntelliJ starting so slowly as to be effectively unusable. One time the entire system appeared to become completely unresponsive & a hard reset was required.
The most recent kernel with which I've experienced problems: $ apt-cache show linux-image-4.9.0-1-amd64 Package: linux-image-4.9.0-1-amd64 Source: linux-signed (4) Version: 4.9.2-2 Installed-Size: 183299 This problem does *not* seem to occur with a vanilla 4.9.2 kernel, implying something Debian-specific: $ uname -a Linux desktop.local 4.9.2 #1 SMP Wed Jan 25 04:28:29 PST 2017 x86_64 GNU/Linux If you're aware of any Debian patches that might be suspect, I'm happy to try some custom builds. Reproducing the issue is trivial on my end when a kernel is "bad". On Sun, Nov 20, 2016 at 2:24 PM, Tom Lee <[email protected]> wrote: > Also potentially relevant: kworker/0:0 has 421h on-cpu time reported per > htop (the TIME+ column) and top. /proc/<pid>/stat output for PID=4 > (kworker/0:0) vs PID=63 (kworker/1:1): > > tom@desktop ~ $ cat /proc/63/stat > 63 (kworker/1:1) S 2 0 0 0 -1 69238880 0 0 0 0 0 0 0 0 20 0 1 0 82 0 0 > 18446744073709551615 0 0 0 0 0 0 0 2147483647 0 0 0 0 17 1 0 0 184 0 0 0 0 > 0 0 0 0 0 0 > tom@desktop ~ $ cat /proc/4/stat > 4 (kworker/0:0) S 2 0 0 0 -1 69238880 0 0 0 0 151836336 0 0 0 20 0 1 0 10 > 0 0 18446744073709551615 0 0 0 0 0 0 0 2147483647 0 0 0 0 17 0 0 0 0 0 0 0 > 0 0 0 0 0 0 0 > > In fact, kworker:0:0 seems to be the only process with on-cpu stats > reported (forgive the shell abuse, quick and dirty): > > $ for pid in $(ls /proc | awk '/^[0-9]*$/'); do [ -d /proc/$pid ] && awk > '$14 != "0" { print $2 }' /proc/$pid/stat; done > (kworker/0:0) > $ > > > On Sun, Nov 20, 2016 at 2:12 PM, Tom Lee <[email protected]> wrote: > >> Tried 4.8.0-1 with similar results. Perhaps slightly better, but not much. >> >> $ uname -a >> Linux desktop 4.8.0-1-amd64 #1 SMP Debian 4.8.5-1 (2016-10-28) x86_64 >> GNU/Linux >> >> Like 4.7, can't see what's hogging the CPUs as per-process CPU stats >> don't appear to be correctly reported in /proc/<pid>/stat. >> >> 4.6.x continues to be perfect with respect to both overall performance >> and the correctness of /proc/<pid>/stat. >> >> >> On Sat, Nov 12, 2016 at 8:23 PM, Ben Hutchings <[email protected]> >> wrote: >> >>> Control: tag -1 moreinfo >>> >>> On Sun, 2016-11-06 at 00:02 -0700, Tom Lee wrote: >>> [...] >>> > Downgrading to linux-image-4.6.0-1-amd64 fixed all symptoms. Haven't >>> yet >>> > tried 4.8.0-1 from unstable, not sure if it's impacted. >>> [...] >>> >>> Please do. >>> >>> Ben. >>> >>> -- >>> Ben Hutchings >>> Nothing is ever a complete failure; it can always serve as a bad >>> example. >>> >>> >> >> >> -- >> *Tom Lee */ http://tomlee.co / @tglee <http://twitter.com/tglee> >> >> > > > -- > *Tom Lee */ http://tomlee.co / @tglee <http://twitter.com/tglee> > > -- *Tom Lee */ http://tomlee.co / @tglee <http://twitter.com/tglee>
