On Wed, 2012-01-25 at 03:30 -0800, Venkat Subbiah wrote: > On 01/25/2012 12:55 AM, Uwe Kleine-König wrote: > > Hello, > > > > On Tue, Jan 24, 2012 at 06:39:34PM -0800, Venkat Subbiah wrote: > >> In the process of debugging a napi ethernet driver performance > >> issue, what I am noticing is > >> > >> 1. While the driver is in the middle of a napi packet processing > >> loop, there is a task switch from > >> sirq-net-rx to idle even though there is pending napi processing to be done. > > I didn't check your logs below, but maybe this is related to the default > > settings in /proc/sys/kernel/sched_rt_period_us and > > /proc/sys/kernel/sched_rt_runtime_us? That is 0.05s per second is > > reserved for non-RT tasks tasks such that a run-away realtime process > > will not lock up the machine. > > > > To verify that, try > > > > echo -1> /proc/sys/kernel/sched_rt_runtime_us > > > > . > Thanks for you response. That was it. Setting this to -1 does the expected. Note, you should also have seen a warning in the logs when an RT task is throttled. Did you see such a thing? -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
