linux-kernel - [tip: x86/cpu] cpufreq: intel_pstate: Avoid SMP calls to get cpu-type

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Message-ID: <174066091933.10177.7411552544696106030.tip-bot2@tip-bot2>
Date: Thu, 27 Feb 2025 12:55:19 -0000
From: "tip-bot2 for Pawan Gupta" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Dave Hansen <dave.hansen@...ux.intel.com>,
 Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
 Ingo Molnar <mingo@...nel.org>,
 Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
 "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: x86/cpu] cpufreq: intel_pstate: Avoid SMP calls to get cpu-type

The following commit has been merged into the x86/cpu branch of tip:

Commit-ID:     b52aaeeadfac54c91005e044b72b62616a5864a9
Gitweb:        https://git.kernel.org/tip/b52aaeeadfac54c91005e044b72b62616a5864a9
Author:        Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>
AuthorDate:    Wed, 11 Dec 2024 22:57:30 -08:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Thu, 27 Feb 2025 13:34:52 +01:00

cpufreq: intel_pstate: Avoid SMP calls to get cpu-type

Intel pstate driver relies on SMP calls to get the cpu-type of a given CPU.
Remove the SMP calls and instead use the cached value of cpu-type which is
more efficient.

[ mingo: Forward ported it. ]

Suggested-by: Dave Hansen <dave.hansen@...ux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Acked-by: Dave Hansen <dave.hansen@...ux.intel.com>
Link: https://lore.kernel.org/r/20241211-add-cpu-type-v5-2-2ae010f50370@linux.intel.com
---
 drivers/cpufreq/intel_pstate.c | 16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 9c4cc01..f06b9bc 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -2200,28 +2200,20 @@ static int knl_get_turbo_pstate(int cpu)
 	return ret;
 }
 
-static void hybrid_get_type(void *data)
-{
-	u8 *cpu_type = data;
-
-	*cpu_type = get_this_hybrid_cpu_type();
-}
-
 static int hwp_get_cpu_scaling(int cpu)
 {
 	if (hybrid_scaling_factor) {
-		u8 cpu_type = 0;
-
-		smp_call_function_single(cpu, hybrid_get_type, &cpu_type, 1);
+		struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
+		u8 cpu_type = c->topo.intel_type;
 
 		/*
 		 * Return the hybrid scaling factor for P-cores and use the
 		 * default core scaling for E-cores.
 		 */
-		if (cpu_type == 0x40)
+		if (cpu_type == INTEL_CPU_TYPE_CORE)
 			return hybrid_scaling_factor;
 
-		if (cpu_type == 0x20)
+		if (cpu_type == INTEL_CPU_TYPE_ATOM)
 			return core_get_scaling();
 	}