From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Zhang Rui <rui.zhang@intel.com>, Chen Yu <yu.c.chen@intel.com>
Subject: [PATCH] cpufreq: intel_pstate: Simplify intel_pstate_update_perf_limits()
Date: Wed, 07 Apr 2021 16:21:55 +0200 [thread overview]
Message-ID: <5450142.DvuYhMxLoT@kreacher> (raw)
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Because pstate.max_freq is always equal to the product of
pstate.max_pstate and pstate.scaling and, analogously,
pstate.turbo_freq is always equal to the product of
pstate.turbo_pstate and pstate.scaling, the result of the
max_policy_perf computation in intel_pstate_update_perf_limits() is
always equal to the quotient of policy_max and pstate.scaling,
regardless of whether or not turbo is disabled. Analogously, the
result of min_policy_perf in intel_pstate_update_perf_limits() is
always equal to the quotient of policy_min and pstate.scaling.
Accordingly, intel_pstate_update_perf_limits() need not check
whether or not turbo is enabled at all and in order to compute
max_policy_perf and min_policy_perf it can always divide policy_max
and policy_min, respectively, by pstate.scaling. Make it do so.
While at it, move the definition and initialization of the
turbo_max local variable to the code branch using it.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
On top of linux-next.
---
drivers/cpufreq/intel_pstate.c | 22 ++++++----------------
1 file changed, 6 insertions(+), 16 deletions(-)
Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -2195,9 +2195,8 @@ static void intel_pstate_update_perf_lim
unsigned int policy_min,
unsigned int policy_max)
{
+ int scaling = cpu->pstate.scaling;
int32_t max_policy_perf, min_policy_perf;
- int max_state, turbo_max;
- int max_freq;
/*
* HWP needs some special consideration, because HWP_REQUEST uses
@@ -2206,33 +2205,24 @@ static void intel_pstate_update_perf_lim
if (hwp_active)
intel_pstate_get_hwp_cap(cpu);
- if (global.no_turbo || global.turbo_disabled) {
- max_state = cpu->pstate.max_pstate;
- max_freq = cpu->pstate.max_freq;
- } else {
- max_state = cpu->pstate.turbo_pstate;
- max_freq = cpu->pstate.turbo_freq;
- }
-
- turbo_max = cpu->pstate.turbo_pstate;
-
- max_policy_perf = max_state * policy_max / max_freq;
+ max_policy_perf = policy_max / scaling;
if (policy_max == policy_min) {
min_policy_perf = max_policy_perf;
} else {
- min_policy_perf = max_state * policy_min / max_freq;
+ min_policy_perf = policy_min / scaling;
min_policy_perf = clamp_t(int32_t, min_policy_perf,
0, max_policy_perf);
}
- pr_debug("cpu:%d max_state %d min_policy_perf:%d max_policy_perf:%d\n",
- cpu->cpu, max_state, min_policy_perf, max_policy_perf);
+ pr_debug("cpu:%d min_policy_perf:%d max_policy_perf:%d\n",
+ cpu->cpu, min_policy_perf, max_policy_perf);
/* Normalize user input to [min_perf, max_perf] */
if (per_cpu_limits) {
cpu->min_perf_ratio = min_policy_perf;
cpu->max_perf_ratio = max_policy_perf;
} else {
+ int turbo_max = cpu->pstate.turbo_pstate;
int32_t global_min, global_max;
/* Global limits are in percent of the maximum turbo P-state. */
next reply other threads:[~2021-04-07 14:22 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-07 14:21 Rafael J. Wysocki [this message]
2021-04-09 12:01 ` [PATCH] cpufreq: intel_pstate: Simplify intel_pstate_update_perf_limits() Chen Yu
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