On 06/06/2018 06:06 PM, Vincent Guittot wrote:
Hi Dietmar,

Sorry for the late answer

On 31 May 2018 at 18:54, Dietmar Eggemann <[email protected]> wrote:
On 05/30/2018 08:45 PM, Vincent Guittot wrote:
Hi Dietmar,

On 30 May 2018 at 17:55, Dietmar Eggemann <[email protected]> wrote:
On 05/25/2018 03:12 PM, Vincent Guittot wrote:

[...]

+        */
+       ret = ___update_load_sum(rq->clock - running, rq->cpu,
&rq->avg_irq,
+                               0,
+                               0,
+                               0);
+       ret += ___update_load_sum(rq->clock, rq->cpu, &rq->avg_irq,
+                               1,
+                               1,
+                               1);

Can you not change the function parameter list to the usual
(u64 now, struct rq *rq, int running)?

Something like this (only compile and boot tested):

To be honest, I prefer to keep the specific sequence above in a
dedicated function instead of adding it in core code.

No big issue.

Furthermore,  we end up calling call twice ___update_load_avg instead
of only once. This will set an intermediate and incorrect value in
util_avg and this value can be read in the meantime

Can't buy this argument though because this is true with the current implementation as well since the 'decay load sum' - 'accrue load sum' sequence is not atomic.

What about calling update_irq_load_avg(rq, 0) in update_rq_clock_task() if (irq_delta + steal) eq. 0 and sched_feat(NONTASK_CAPACITY) eq. true in this #ifdef CONFIG_XXX_TIME_ACCOUNTING block?

Maintaining a irq/steal time signal makes only sense if at least one of the CONFIG_XXX_TIME_ACCOUNTING is set and NONTASK_CAPACITY is true. The call to update_irq_load_avg() in update_blocked_averages() isn't guarded my them.

[...]

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