Re: [PATCH 17/18] sched: Tracepoint task movement

[Mel Gorman]

On Mon, Dec 09, 2013 at 01:54:51PM -0500, Rik van Riel wrote:
> On 12/09/2013 02:09 AM, Mel Gorman wrote:
> > move_task() is called from move_one_task and move_tasks and is an
> > approximation of load balancer activity. We should be able to track
> > tasks that move between CPUs frequently. If the tracepoint included node
> > information then we could distinguish between in-node and between-node
> > traffic for load balancer decisions. The tracepoint allows us to track
> > local migrations, remote migrations and average task migrations.
> > 
> > Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
> 
> Does this replicate the task_sched_migrate_task tracepoint in
> set_task_cpu() ?
> 

There is significant overlap but bits missing. We do not necessarily know
where the task was previously running and whether this is a local->remote
migration. We also cannot tell the difference between load balancer activity,
numa balancing and try_to_wake_up. Still, you're right, this patch is not
painting a full picture either. I'll drop it for now and look at improving
the existing task_sched_migrate_task tracepoint.

-- 
Mel Gorman
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/