Messages in this thread | | | Date | Sat, 26 Jun 2010 18:47:09 +0200 | Subject | Re: 2.6.35-rc3: System unresponsive under load | From | Luca Tettamanti <> |
| |
On Sat, Jun 26, 2010 at 5:47 PM, Manfred Spraul <manfred@colorfullife.com> wrote: > Hi Luca, > > On 06/26/2010 02:52 PM, Luca Tettamanti wrote: >> >> They don't seem really hung as before, I see two different behaviours: >> * Near the end of the run ab is frozen for a few seconds, but in the >> end all requests are processed; however I see a few "length" errors, >> meaning that the received page does not match the expected content >> (I'm testing a static page): >> >> > > That's consistent with what I see: > If I run: > #./semtimedop 100 100& > #./semtimedop 100 100& > #./semtimedop 100 100& > #./semtimedop 100 100& > > (i.e.: 4 times the attached test app concurrently), then the system > sometimes locks up for 10..20 seconds: > The keyboard is unresponsive, not even the numlock key is processed (i.e.: > the LED does not change anymore). > After 10 or 20 seconds, the keyboard reacts again (both to <enter> and to > Num Lock) > The stock Fedora 13 kernel (2.6.33.5) does not exhibit this behavior > The load average is 300 or so, that's expected.
Confirmed here: your test program freezes the system for a while under 2.6.35-rc3, while vanilla 2.6.34 copes fine. sysrq-t was responsive during the freeze, so I took a snapshot during it, file is attached.
> I have no idea why and how to debug the behavior. > # CONFIG_PREEMPT_NONE is not set > CONFIG_PREEMPT_VOLUNTARY=y > # CONFIG_PREEMPT is not set
My kernel has PREEMPT enabled.
Luca [unhandled content-type:application/x-gzip] | |