Subject: Re: [PATCH] rcu: Eliminate softirq processing from rcutree

* Mike Galbraith | 2013-12-23 06:12:39 [+0100]:

>P.S.
>
>virgin -rt7 doing tbench 64 + make -j64
>
>[ 97.907960] perf samples too long (3138 > 2500), lowering kernel.perf_event_max_sample_rate to 50000
>[ 103.047921] perf samples too long (5544 > 5000), lowering kernel.perf_event_max_sample_rate to 25000
>[ 181.561271] perf samples too long (10318 > 10000), lowering kernel.perf_event_max_sample_rate to 13000
>[ 184.243750] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 1.084 msecs
>[ 248.914422] perf samples too long (19719 > 19230), lowering kernel.perf_event_max_sample_rate to 7000
>[ 382.116674] NOHZ: local_softirq_pending 10
This is block

>[ 405.201593] perf samples too long (36824 > 35714), lowering kernel.perf_event_max_sample_rate to 4000
>[ 444.704185] NOHZ: local_softirq_pending 08
>[ 444.704208] NOHZ: local_softirq_pending 08
>[ 444.704579] NOHZ: local_softirq_pending 08
>[ 444.704678] NOHZ: local_softirq_pending 08
>[ 444.705100] NOHZ: local_softirq_pending 08
>[ 444.705980] NOHZ: local_softirq_pending 08
>[ 444.705994] NOHZ: local_softirq_pending 08
>[ 444.708315] NOHZ: local_softirq_pending 08
>[ 444.710348] NOHZ: local_softirq_pending 08

and this is RX. Is your testcase heavy disk-io or heavy disk-io +
network?

Sebastian


2014-01-25 05:20:41

by Mike Galbraith

[permalink] [raw]
Subject: Re: [PATCH] rcu: Eliminate softirq processing from rcutree

On Fri, 2014-01-24 at 20:46 +0100, Sebastian Andrzej Siewior wrote:
> * Mike Galbraith | 2013-12-23 06:12:39 [+0100]:
>
> >P.S.
> >
> >virgin -rt7 doing tbench 64 + make -j64
> >
> >[ 97.907960] perf samples too long (3138 > 2500), lowering kernel.perf_event_max_sample_rate to 50000
> >[ 103.047921] perf samples too long (5544 > 5000), lowering kernel.perf_event_max_sample_rate to 25000
> >[ 181.561271] perf samples too long (10318 > 10000), lowering kernel.perf_event_max_sample_rate to 13000
> >[ 184.243750] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 1.084 msecs
> >[ 248.914422] perf samples too long (19719 > 19230), lowering kernel.perf_event_max_sample_rate to 7000
> >[ 382.116674] NOHZ: local_softirq_pending 10
> This is block
>
> >[ 405.201593] perf samples too long (36824 > 35714), lowering kernel.perf_event_max_sample_rate to 4000
> >[ 444.704185] NOHZ: local_softirq_pending 08
> >[ 444.704208] NOHZ: local_softirq_pending 08
> >[ 444.704579] NOHZ: local_softirq_pending 08
> >[ 444.704678] NOHZ: local_softirq_pending 08
> >[ 444.705100] NOHZ: local_softirq_pending 08
> >[ 444.705980] NOHZ: local_softirq_pending 08
> >[ 444.705994] NOHZ: local_softirq_pending 08
> >[ 444.708315] NOHZ: local_softirq_pending 08
> >[ 444.710348] NOHZ: local_softirq_pending 08
>
> and this is RX. Is your testcase heavy disk-io or heavy disk-io +
> network?

Yeah.

-Mike