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cpufreq: intel_pstate: Avoid SMP calls to get cpu-type
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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@linux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20241211-add-cpu-type-v5-2-2ae010f50370@linux.intel.com
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Pawan Gupta authored and Ingo Molnar committed Feb 27, 2025
1 parent 4a412c7 commit b52aaee
Showing 1 changed file with 4 additions and 12 deletions.
16 changes: 4 additions & 12 deletions drivers/cpufreq/intel_pstate.c
Original file line number Diff line number Diff line change
Expand Up @@ -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();
}

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