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Odward
n00b
Joined: 21 Mar 2012
Posts: 65
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 Posted: Wed Apr 09, 2014 7:38 am Post subject: gentoo-sources-3.12.13 and ksoftirqd cpu usage |
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After upgrading from gentoo-sources-3.10.25 to 3.12.13 I noticed my CPU temp was up and my activity monitor widget indicated CPU usage when it should have been idle.
Using top I see that ksoftirqd/X has 1 or 2 cores, varies from 1 boot to the next, pegged 98-100% non stop. I can reboot with kernel 3.10.25 and the problem disappears.
I don't have any idea how to begin diagnosing interrupt problems.
Checking cat /proc/interrupts after 1 boot into each kernel, to the console. Both examples are approx 5 minutes uptime. Edited for space to show offending interrupt.
Kernel-3.10.25
| Code: | CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
LOC: 570 871 2725 975 1497 929 751 771 Local timer interrupts
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Kernel-3.12.13 (Only ksoftirqd/2 on this boot, frequently will be a second i.e. ksoftirqd/0)
| Code: | CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
LOC: 853 3423 60663 818 877 614 36 953 Local timer interrupts
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There were also more differences with the resulting .config after compiling the new kernel, but just randomly checking for IRQ in the diff I see kernel 3.10.25 contains
| Code: | < CONFIG_HAVE_GENERIC_HARDIRQS=y
< CONFIG_GENERIC_HARDIRQS=y |
Those do not exist for 3.12.13 and if I read correctly those are set by X86=y and both kernel .configs contain
Curious if anyone can give me a more clear nudge in the right direction. I have no problem sticking with 3.10.25 but I'm concerned if I don't figure out the right kernel config I could have this issue with any newer kernels. I suppose I could try a newer kernel =) but maybe I learn something this way too.
Thanks for your time |
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Keruskerfuerst
Advocate
Joined: 01 Feb 2006
Posts: 2289
Location: near Augsburg, Germany
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| Posted: Thu Apr 10, 2014 7:06 pm Post subject: |
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| How did you configure the new kernel? |
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Odward
n00b
Joined: 21 Mar 2012
Posts: 65
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| Posted: Fri Apr 11, 2014 6:45 am Post subject: |
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In a nutshell, I just copy the .config for the existing kernel. After issuing 'make menuconfig' for the new kernel I exit and am prompted to save my config. I run make && make modules_install from there. Copy to boot etc.
I've been doing that for a bit over 2 years now, since I started using Gentoo (linux for that matter). This is the same hardware on which it's been running that time too. Originally I took the time to create a kernel appropriate for my hardware, to the best of my ability, and then the above method ever since. |
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Kernel & Hardware
