On Tue, 2 Dec 2014 14:26:55 -0500 Tejun Heo <tj@xxxxxxxxxx> wrote: > On Tue, Dec 02, 2014 at 02:18:14PM -0500, Tejun Heo wrote: > ... > > unbound. If strict cpu locality is likely to be beneficial and each > > work item isn't likely to consume huge amount of cpu cycles, > > WQ_CPU_INTENSIVE would fit better; otherwise, WQ_UNBOUND to let the > > scheduler do its thing. > > Hmmm... but you're already using WQ_UNBOUND. Concurrency management > doesn't matter for unbound workqueues. They really just behave as > shared worker thread pools. Does turning on WQ_HIGHPRI change > anything? Workqueue always prefers hot workers which can lead to the > hot ones being penalized for consuming too much CPU time. > > Thanks. > WQ_HIGHPRI doesn't seem to help. FWIW, here's the fio status line from that test: threaded nfsd: WRITE: io=12628KB, aggrb=210KB/s, minb=52KB/s, maxb=52KB/s, mint=60064msec, maxt=60107msec workqueue nfsd: WRITE: io=7464KB, aggrb=124KB/s, minb=30KB/s, maxb=31KB/s, mint=60066msec, maxt=60133msec ...and the workqueue numbers didn't change much from the case without WQ_HIGHPRI. I didn't gather significant queueing latency numbers for that run but I can get those together tomorrow. My fio test config follows for anyone who's interested (it's tiobench-example.fio without the read tests): -------------------------[snip]-------------------------- [global] direct=1 size=128m bsrange=4k-4k timeout=60 numjobs=4 ; 4 simultaneous threads for each job [f1] rw=write -------------------------[snip]-------------------------- ... the server in this case is an older quad core AMD Phenom CPU, with a 5400rpm SATA disk under it on a 3Gbps SATA interface. The client is mounting it using NFSv3 and I'm only running a single client here. The only difference between the two tests above is that whether nfsd is running with the sunrpc.ko pool_mode set to "global" or "workqueue". -- Jeff Layton <jlayton@xxxxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
