After booting the gentoo-sources-4.2.0 kernel I can see all my CPU cores in lscpu, htop etc. but all applications and threads are running on the first core only. All other cores are idle. Issue is affecting all my tested machines (one AMD, one Intel and one ARM). This does not happen with vanilla-sources-4.2.0. I'm not sure what's causing this. Reproducible: Always Steps to Reproduce: 1. emerge gentoo-sources-4.2.0, configure and build kernel 2. boot kernel 3. watch in htop while running "7z b" (p7zip), ffmpeg encode with libx264 (multithread) or other applications normally using multiple cores. Actual Results: first core is doing all the work, system performance goes down. All other cores are idle. Expected Results: Applications and threads are shared over all cores.
Same here. 1. emerge gentoo-sources-4.2.0 2. get config from 4.1.6 (zcat /proc/config.gz >.config) 3. book new kernel - only one core working from four (in top there are four cores) For me vanilla-sources-4.2.0 also not working. Again one core from four.
Try CONFIG_NO_HZ_IDLE=y # CONFIG_NO_HZ_FULL is not set
fyi: https://bugzilla.kernel.org/show_bug.cgi?id=101021
@josef.95 Thanks for your hint! My machines are fully functional again now.
Not fixed, judging by bug #559382.
*** Bug 559556 has been marked as a duplicate of this bug. ***
I get same issue.
4.2.1 has same issue
(In reply to Alexey Shvetsov from comment #8) > 4.2.1 has same issue Did you try this? CONFIG_NO_HZ_COMMON=y CONFIG_NO_HZ_IDLE=y # CONFIG_NO_HZ_FULL is not set CONFIG_NO_HZ=y
4.2.2 has same problem. P.S. for Mike Pagano "when NO_HZ_FULL is set"
(In reply to Artemii from comment #10) > 4.2.2 has same problem. > > P.S. for Mike Pagano "when NO_HZ_FULL is set" Can you do me a favor please and try the above with git-sources ? The latest version if you don't mind.
(In reply to Mike Pagano from comment #11) > Can you do me a favor please and try the above with git-sources ? > > The latest version if you don't mind. 4.3-rc3 still has same problem.
(In reply to Artemii from comment #12) > (In reply to Mike Pagano from comment #11) > > Can you do me a favor please and try the above with git-sources ? > > > > The latest version if you don't mind. > > 4.3-rc3 still has same problem. What do you have for NO_HZ_FULL ?
(In reply to Mike Pagano from comment #13) > (In reply to Artemii from comment #12) > > > > 4.3-rc3 still has same problem. > > What do you have for NO_HZ_FULL ? CONFIG_NO_HZ_FULL=y CONFIG_NO_HZ_FULL_ALL=y # CONFIG_NO_HZ_FULL_SYSIDLE is not set cpuinfo tell about eight cores AMD FX(tm)-8120
(In reply to Artemii from comment #14) > (In reply to Mike Pagano from comment #13) > > (In reply to Artemii from comment #12) > > > > > > 4.3-rc3 still has same problem. > > > > What do you have for NO_HZ_FULL ? > > CONFIG_NO_HZ_FULL=y > CONFIG_NO_HZ_FULL_ALL=y > # CONFIG_NO_HZ_FULL_SYSIDLE is not set > > cpuinfo tell about eight cores AMD FX(tm)-8120 try this CONFIG_NO_HZ_COMMON=y CONFIG_NO_HZ_IDLE=y # CONFIG_NO_HZ_FULL is not set CONFIG_NO_HZ=y
(In reply to Mike Pagano from comment #15) > try this > > CONFIG_NO_HZ_COMMON=y > CONFIG_NO_HZ_IDLE=y > # CONFIG_NO_HZ_FULL is not set > CONFIG_NO_HZ=y In this case multicore scheduling works fine.
still seeing this with 4.2.3
kernel 4.3-rc6 also affected. Tested on x86 and armv7l
Another fun error. If SERVER PREEMPTION set also all tasks will go to core0
This is probably the relevant LKML thread response https://lkml.org/lkml/2015/7/15/762