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From: Peter Zijlstra <peterz@infradead.org>
To: anna-maria@linutronix.de, rafael@kernel.org, tglx@linutronix.de,
	frederic@kernel.org, gautham.shenoy@amd.com
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
	daniel.lezcano@linaro.org, linux-pm@vger.kernel.org,
	mingo@redhat.com, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	bristot@redhat.com, vschneid@redhat.com,
	kajetan.puchalski@arm.com
Subject: [RFC][PATCH v2 3/5] cpuidle/teo: Simplify a little
Date: Wed, 02 Aug 2023 15:24:34 +0200	[thread overview]
Message-ID: <20230802132925.686745535@infradead.org> (raw)
In-Reply-To: 20230802132431.254614419@infradead.org

Remove some of the early exit cases that rely on state_count, since we
have the additional tick state. Declutters some of the next patches, can
possibly be re-instated later if desired.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 drivers/cpuidle/governors/teo.c |   31 +------------------------------
 1 file changed, 1 insertion(+), 30 deletions(-)

--- a/drivers/cpuidle/governors/teo.c
+++ b/drivers/cpuidle/governors/teo.c
@@ -187,7 +187,6 @@ struct teo_bin {
  * @next_recent_idx: Index of the next @recent_idx entry to update.
  * @recent_idx: Indices of bins corresponding to recent "intercepts".
  * @util_threshold: Threshold above which the CPU is considered utilized
- * @utilized: Whether the last sleep on the CPU happened while utilized
  */
 struct teo_cpu {
 	s64 time_span_ns;
@@ -197,7 +196,6 @@ struct teo_cpu {
 	int next_recent_idx;
 	int recent_idx[NR_RECENT];
 	unsigned long util_threshold;
-	bool utilized;
 };
 
 static DEFINE_PER_CPU(struct teo_cpu, teo_cpus);
@@ -379,33 +377,6 @@ static int teo_select(struct cpuidle_dri
 	duration_ns = tick_nohz_get_sleep_length(&delta_tick);
 	cpu_data->sleep_length_ns = duration_ns;
 
-	/* Check if there is any choice in the first place. */
-	if (drv->state_count < 2) {
-		idx = 0;
-		goto end;
-	}
-	if (!dev->states_usage[0].disable) {
-		idx = 0;
-		if (drv->states[1].target_residency_ns > duration_ns)
-			goto end;
-	}
-
-	cpu_data->utilized = teo_cpu_is_utilized(dev->cpu, cpu_data);
-	/*
-	 * If the CPU is being utilized over the threshold and there are only 2
-	 * states to choose from, the metrics need not be considered, so choose
-	 * the shallowest non-polling state and exit.
-	 */
-	if (drv->state_count < 3 && cpu_data->utilized) {
-		for (i = 0; i < drv->state_count; ++i) {
-			if (!dev->states_usage[i].disable &&
-			    !(drv->states[i].flags & CPUIDLE_FLAG_POLLING)) {
-				idx = i;
-				goto end;
-			}
-		}
-	}
-
 	/*
 	 * Find the deepest idle state whose target residency does not exceed
 	 * the current sleep length and the deepest idle state not deeper than
@@ -541,7 +512,7 @@ static int teo_select(struct cpuidle_dri
 	 * If the CPU is being utilized over the threshold, choose a shallower
 	 * non-polling state to improve latency
 	 */
-	if (cpu_data->utilized)
+	if (teo_cpu_is_utilized(dev->cpu, cpu_data))
 		idx = teo_find_shallower_state(drv, dev, idx, duration_ns, true);
 
 end:



  parent reply	other threads:[~2023-08-02 13:31 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-02 13:24 [RFC][PATCH v2 0/5] cpuidle,teo: Improve TEO vs NOHZ Peter Zijlstra
2023-08-02 13:24 ` [RFC][PATCH v2 1/5] tick/nohz: Introduce tick_get_sleep_length() Peter Zijlstra
2023-08-02 13:24 ` [RFC][PATCH v2 2/5] cpuidle: Inject tick boundary state Peter Zijlstra
2023-08-02 13:24 ` Peter Zijlstra [this message]
2023-08-03 10:12   ` [RFC][PATCH v2 3/5] cpuidle/teo: Simplify a little Kajetan Puchalski
2023-08-02 13:24 ` [RFC][PATCH v2 4/5] cpuidle/teo: Avoid tick_nohz_next_event() Peter Zijlstra
2023-08-02 13:24 ` [RFC][PATCH v2 5/5] cpuidle,teo: Improve state selection Peter Zijlstra

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