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Message-Id: <20240905092645.2885200-7-christian.loehle@arm.com>
Date: Thu, 5 Sep 2024 10:26:43 +0100
From: Christian Loehle <christian.loehle@....com>
To: linux-pm@...r.kernel.org,
linux-kernel@...r.kernel.org,
rafael@...nel.org,
peterz@...radead.org
Cc: juri.lelli@...hat.com,
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Christian Loehle <christian.loehle@....com>
Subject: [RFC PATCH 6/8] cpufreq: intel_pstate: Remove iowait boost
Analogous to schedutil, remove iowait boost for the same reasons.
Signed-off-by: Christian Loehle <christian.loehle@....com>
---
drivers/cpufreq/intel_pstate.c | 50 ++--------------------------------
1 file changed, 3 insertions(+), 47 deletions(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index c0278d023cfc..7f30b2569bb3 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -191,7 +191,6 @@ struct global_params {
* @policy: CPUFreq policy value
* @update_util: CPUFreq utility callback information
* @update_util_set: CPUFreq utility callback is set
- * @iowait_boost: iowait-related boost fraction
* @last_update: Time of the last update.
* @pstate: Stores P state limits for this CPU
* @vid: Stores VID limits for this CPU
@@ -245,7 +244,6 @@ struct cpudata {
struct acpi_processor_performance acpi_perf_data;
bool valid_pss_table;
#endif
- unsigned int iowait_boost;
s16 epp_powersave;
s16 epp_policy;
s16 epp_default;
@@ -2136,28 +2134,7 @@ static inline void intel_pstate_update_util_hwp_local(struct cpudata *cpu,
{
cpu->sample.time = time;
- if (cpu->sched_flags & SCHED_CPUFREQ_IOWAIT) {
- bool do_io = false;
-
- cpu->sched_flags = 0;
- /*
- * Set iowait_boost flag and update time. Since IO WAIT flag
- * is set all the time, we can't just conclude that there is
- * some IO bound activity is scheduled on this CPU with just
- * one occurrence. If we receive at least two in two
- * consecutive ticks, then we treat as boost candidate.
- */
- if (time_before64(time, cpu->last_io_update + 2 * TICK_NSEC))
- do_io = true;
-
- cpu->last_io_update = time;
-
- if (do_io)
- intel_pstate_hwp_boost_up(cpu);
-
- } else {
- intel_pstate_hwp_boost_down(cpu);
- }
+ intel_pstate_hwp_boost_down(cpu);
}
static inline void intel_pstate_update_util_hwp(struct update_util_data *data,
@@ -2240,9 +2217,6 @@ static inline int32_t get_target_pstate(struct cpudata *cpu)
busy_frac = div_fp(sample->mperf << cpu->aperf_mperf_shift,
sample->tsc);
- if (busy_frac < cpu->iowait_boost)
- busy_frac = cpu->iowait_boost;
-
sample->busy_scaled = busy_frac * 100;
target = READ_ONCE(global.no_turbo) ?
@@ -2303,7 +2277,7 @@ static void intel_pstate_adjust_pstate(struct cpudata *cpu)
sample->aperf,
sample->tsc,
get_avg_frequency(cpu),
- fp_toint(cpu->iowait_boost * 100));
+ 0);
}
static void intel_pstate_update_util(struct update_util_data *data, u64 time,
@@ -2317,24 +2291,6 @@ static void intel_pstate_update_util(struct update_util_data *data, u64 time,
return;
delta_ns = time - cpu->last_update;
- if (flags & SCHED_CPUFREQ_IOWAIT) {
- /* Start over if the CPU may have been idle. */
- if (delta_ns > TICK_NSEC) {
- cpu->iowait_boost = ONE_EIGHTH_FP;
- } else if (cpu->iowait_boost >= ONE_EIGHTH_FP) {
- cpu->iowait_boost <<= 1;
- if (cpu->iowait_boost > int_tofp(1))
- cpu->iowait_boost = int_tofp(1);
- } else {
- cpu->iowait_boost = ONE_EIGHTH_FP;
- }
- } else if (cpu->iowait_boost) {
- /* Clear iowait_boost if the CPU may have been idle. */
- if (delta_ns > TICK_NSEC)
- cpu->iowait_boost = 0;
- else
- cpu->iowait_boost >>= 1;
- }
cpu->last_update = time;
delta_ns = time - cpu->sample.time;
if ((s64)delta_ns < INTEL_PSTATE_SAMPLING_INTERVAL)
@@ -2832,7 +2788,7 @@ static void intel_cpufreq_trace(struct cpudata *cpu, unsigned int trace_type, in
sample->aperf,
sample->tsc,
get_avg_frequency(cpu),
- fp_toint(cpu->iowait_boost * 100));
+ 0);
}
static void intel_cpufreq_hwp_update(struct cpudata *cpu, u32 min, u32 max,
--
2.34.1
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