Messages in this thread | | | Subject | Re: [PATCH] Migration of Standard Timers | From | Lee Revell <> | Date | Tue, 19 Sep 2006 12:57:53 -0400 |
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On Tue, 2006-09-19 at 11:41 -0500, Dimitri Sivanich wrote: > On Tue, Sep 19, 2006 at 12:33:37PM -0400, Lee Revell wrote: > > Which driver or subsystem is doing 100s of usecs of work in a timer? > > The longest one I've captured so far results from: > > rsp rip Function (args) > ======================= <nmi> > 0xffff810257822fd8 0xffffffff803a0e94 rt_check_expire+0x8c > ======================= <interrupt> > 0xffff81025781fee8 0xffffffff803a0e08 rt_check_expire > 0xffff81025781ff08 0xffffffff802386b3 run_timer_softirq+0x133 > 0xffff81025781ff38 0xffffffff80235262 __do_softirq+0x5e > 0xffff81025781ff68 0xffffffff8020a958 call_softirq+0x1c > 0xffff81025781ff80 0xffffffff8020bea7 do_softirq+0x2c > 0xffff81025781ff90 0xffffffff80235142 irq_exit+0x48 >
Ah, I remember that one. Eric Dumazet had some suggestions to fix it 6-12 months ago which never went anywhere - the thread was called "RCU latency regression in 2.6.16-rc1".
That one is especially annoying as there's no workaround (shrinking the route cache or reducing the GC interval via net.ipv4.route.* sysctls has no effect)
Lee
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