Messages in this thread | | | Date | Wed, 09 Feb 2011 10:47:10 -0700 | From | David Ahern <> | Subject | Re: perf on 2.6.38-rc4 wedges my box |
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On 02/09/11 10:38, Jeff Moyer wrote: > Hi, > > I'm trying out willy's ata_ram driver[1], and in so doing have managed to > wedge my box while using perf record on an aio-stress run: > > [root@metallica ~]# modprobe ata_ram capacity=2097152 preallocate=1 > [root@metallica ~]# ./aio-stress -O -o 0 -r 4 -d 32 -b 16 /dev/sds > adding stage write > starting with write > file size 1024MB, record size 4KB, depth 32, ios per iteration 8 > max io_submit 16, buffer alignment set to 4KB > threads 1 files 1 contexts 1 context offset 2MB verification off > adding file /dev/sds thread 0 > write on /dev/sds (621.30 MB/s) 1024.00 MB in 1.65s > thread 0 write totals (621.27 MB/s) 1024.00 MB in 1.65s > [root@metallica ~]# perf record -- ./aio-stress -O -o 0 -r 4 -d 32 -b 16 > /dev/sds
Have you tried '-e cpu-clock' for S/W based profiling vs the default H/W profiling? Add -v to see if the fallback to S/W is happening now.
David
> adding stage write > starting with write > file size 1024MB, record size 4KB, depth 32, ios per iteration 8 > max io_submit 16, buffer alignment set to 4KB > threads 1 files 1 contexts 1 context offset 2MB verification off > adding file /dev/sds thread 0 > > and there it sits. On the console, I see: > > NOHZ: local_softirq_pending 100 > NOHZ: local_softirq_pending 100 > NOHZ: local_softirq_pending 100 > NOHZ: local_softirq_pending 100 > NOHZ: local_softirq_pending 100 > > The number of messages varies, but this is the most I've seen (it > doesn't keep repeating). At this point, the machine does not respond to > pings. As I don't have physical access at the moment, I can't try > alt-sysrq, but might be able to do that tomorrow. It's probably worth > noting that I've witnessed similar behavior with real devices, so it's > not just the ata_ram driver. > > Any ideas on how to track this down? > > Thanks! > > Jeff > > [1] http://git.kernel.org/?p=linux/kernel/git/willy/misc.git;a=shortlog;h=refs/heads/ata-ram > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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