On 08/23/2016 03:11 PM, Jens Axboe wrote:
On 08/23/2016 02:54 PM, Gabriel Krisman Bertazi wrote:
Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxxxxxxx> writes:
Can you share what you ran to online/offline CPUs? I can't reproduce
this here.
I was using the ppc64_cpu tool, which shouldn't do nothing more than
write to sysfs. but I just reproduced it with the script below.
Note that this is ppc64le. I don't have a x86 in hand to attempt to
reproduce right now, but I'll look for one and see how it goes.
Hi,
Any luck on reproducing it? We were initially reproducing with a
proprietary stress test, but I gave a try to a generated fio jobfile
associated with the SMT script I shared earlier and I could reproduce
the crash consistently in less than 10 minutes of execution. this was
still ppc64le, though. I couldn't get my hands on nvme on x86 yet.
Nope, I have not been able to reproduce it. How long does the CPU
offline/online actions take on ppc64? It's pretty slow on x86, which may
hide the issue. I took out the various printk's associated with bringing
a CPU off/online, as well as IRQ breaking parts, but didn't help in
reproducing it.
The job file I used, as well as the smt.sh script, in case you want to
give it a try:
jobfile: http://krisman.be/k/nvmejob.fio
smt.sh: http://krisman.be/k/smt.sh
Still, the trigger seems to be consistently a heavy load of IO
associated with CPU addition/removal.
My workload looks similar to yours, in that it's high depth and with a
lot of jobs to keep most CPUs loaded. My bash script is different than
yours, I'll try that and see if it helps here.
Actually, I take that back. You're not using O_DIRECT, hence all your
jobs are running at QD=1, not the 256 specified. That looks odd, but
I'll try, maybe it'll hit something different.
--
Jens Axboe
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