On 30/11/17 15:45, Patrick Bellasi wrote:

On 30-Nov 14:17, Juri Lelli wrote:

quoted

Hi,

On 30/11/17 11:47, Patrick Bellasi wrote:

[...]

quoted

@@ -340,6 +349,7 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
 	struct sugov_policy *sg_policy = sg_cpu->sg_policy;
 	unsigned long util, max;
 	unsigned int next_f;
+	bool rt_mode;
 
 	sugov_get_util(&util, &max, sg_cpu->cpu);
 

@@ -353,17 +363,27 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
 		sg_cpu->flags = 0;
 		goto done;
 	}
-	sg_cpu->flags = flags;
+
+	/*
+	 * While RT/DL tasks are running we do not want FAIR tasks to
+	 * overwrite this CPU's flags, still we can update utilization and
+	 * frequency (if required/possible) to be fair with these tasks.
+	 */
+	rt_mode = task_has_dl_policy(current) ||
+		  task_has_rt_policy(current) ||
+		  (flags & SCHED_CPUFREQ_RT_DL);
+	if (rt_mode)
+		sg_cpu->flags |= flags;
+	else
+		sg_cpu->flags = flags;
 
 	sugov_set_iowait_boost(sg_cpu, time, flags);
 	sg_cpu->last_update = time;
 
 	if (sugov_should_update_freq(sg_policy, time)) {
-		if (flags & SCHED_CPUFREQ_RT_DL)
-			next_f = sg_policy->policy->cpuinfo.max_freq;
-		else
-			next_f = sugov_next_freq_shared(sg_cpu, time);
-
+		next_f = rt_mode
+			? sg_policy->policy->cpuinfo.max_freq
+			: sugov_next_freq_shared(sg_cpu, time);
 		sugov_update_commit(sg_policy, time, next_f);

Aren't we already at max_freq at this point (since an RT/DL task is
running)? Do we need to trigger a frequency update?

I think that's required to cover the first time we enter rt_mode in
order to jump to max OPP.

If we are already at max OPP, sugov_update_commit() will just bail out
without doing anything.

Indeed!

Best,

Juri