* [PATCH 1/2] x86/cpufeatures: Add AMD FAST CPPC feature flag
@ 2024-04-29 7:03 Xiaojian Du
2024-04-29 7:03 ` [PATCH 2/2] cpufreq: amd-pstate: change cpu freq transition delay for some models Xiaojian Du
0 siblings, 1 reply; 4+ messages in thread
From: Xiaojian Du @ 2024-04-29 7:03 UTC (permalink / raw)
To: linux-kernel, linux-pm
Cc: tglx, mingo, bp, dave.hansen, hpa, daniel.sneddon, jpoimboe,
pawan.kumar.gupta, sandipan.das, kai.huang, perry.yuan, x86,
ray.huang, rafael, Xiaojian Du
From: Perry Yuan <perry.yuan@amd.com>
Some AMD Zen 4 processors support a new feature FAST CPPC which
allows for a faster CPPC loop due to internal architectual
enhancements. The goal of this faster loop is higher performance
at the same power consumption.
Reference:
See the page 99 of PPR for AMD Family 19h Model 61h rev.B1, docID 56713
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Xiaojian Du <Xiaojian.Du@amd.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
---
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/kernel/cpu/scattered.c | 1 +
2 files changed, 2 insertions(+)
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 3c7434329661..6c128d463a14 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -470,6 +470,7 @@
#define X86_FEATURE_BHI_CTRL (21*32+ 2) /* "" BHI_DIS_S HW control available */
#define X86_FEATURE_CLEAR_BHB_HW (21*32+ 3) /* "" BHI_DIS_S HW control enabled */
#define X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT (21*32+ 4) /* "" Clear branch history at vmexit using SW loop */
+#define X86_FEATURE_FAST_CPPC (21*32 + 5) /* "" AMD Fast CPPC */
/*
* BUG word(s)
diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index af5aa2c754c2..9c273c231f56 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -51,6 +51,7 @@ static const struct cpuid_bit cpuid_bits[] = {
{ X86_FEATURE_PERFMON_V2, CPUID_EAX, 0, 0x80000022, 0 },
{ X86_FEATURE_AMD_LBR_V2, CPUID_EAX, 1, 0x80000022, 0 },
{ X86_FEATURE_AMD_LBR_PMC_FREEZE, CPUID_EAX, 2, 0x80000022, 0 },
+ { X86_FEATURE_FAST_CPPC, CPUID_EDX, 15, 0x80000007, 0 },
{ 0, 0, 0, 0, 0 }
};
--
2.34.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH 2/2] cpufreq: amd-pstate: change cpu freq transition delay for some models
2024-04-29 7:03 [PATCH 1/2] x86/cpufeatures: Add AMD FAST CPPC feature flag Xiaojian Du
@ 2024-04-29 7:03 ` Xiaojian Du
2024-05-11 6:54 ` Yuan, Perry
2024-05-22 16:46 ` Mario Limonciello
0 siblings, 2 replies; 4+ messages in thread
From: Xiaojian Du @ 2024-04-29 7:03 UTC (permalink / raw)
To: linux-kernel, linux-pm
Cc: tglx, mingo, bp, dave.hansen, hpa, daniel.sneddon, jpoimboe,
pawan.kumar.gupta, sandipan.das, kai.huang, perry.yuan, x86,
ray.huang, rafael, Xiaojian Du, Mario Limonciello
Some of AMD ZEN4 APU/CPU have support for adjusting the CPU core
clock more quickly and presicely according to CPU work loading.
This is advertised by the Fast CPPC x86 feature.
This change will only be effective in the *passive mode* of
AMD pstate driver. From the test results of different
transition delay values, 600us is chosen to make a balance
between performance and power consumption.
Some test results on AMD Ryzen 7840HS(Phoenix) APU:
1. Tbench
(Energy less is better, Throughput more is better,
PPW--Performance per Watt more is better)
============= =================== ============== =============== ============== =============== ============== =============== ===============
Trans Delay Tbench governor:schedutil, 3-iterations average
============= =================== ============== =============== ============== =============== ============== =============== ===============
1000us Clients 1 2 4 8 12 16 32
Energy/Joules 2010 2804 8768 17171 16170 15132 15027
Throughput/(MB/s) 114 259 1041 3010 3135 4851 4605
PPW 0.0567 0.0923 0.1187 0.1752 0.1938 0.3205 0.3064
600us Clients 1 2 4 8 12 16 32
Energy/Joules 2115 (5.22%) 2388 (-14.84%) 10700(22.03%) 16716 (-2.65%) 15939 (-1.43%) 15053 (-0.52%) 15083 (0.37% )
Throughput/(MB/s) 122 (7.02%) 234 (-9.65% ) 1188 (14.12%) 3003 (-0.23%) 3143 (0.26% ) 4842 (-0.19%) 4603 (-0.04%)
PPW 0.0576(1.59%) 0.0979(6.07% ) 0.111(-6.49%) 0.1796(2.51% ) 0.1971(1.70% ) 0.3216(0.34% ) 0.3051(-0.42%)
============= =================== ============== ================ ============= =============== ============== =============== ===============
2.Dbench
(Energy less is better, Throughput more is better,
PPW--Performance per Watt more is better)
============= =================== ============== =============== ============== =============== ============== =============== ===============
Trans Delay Dbench governor:schedutil, 3-iterations average
============= =================== ============== =============== ============== =============== ============== =============== ===============
1000us Clients 1 2 4 8 12 16 32
Energy/Joules 4890 3779 3567 5157 5611 6500 8163
Throughput/(MB/s) 327 167 220 577 775 938 1397
PPW 0.0668 0.0441 0.0616 0.1118 0.1381 0.1443 0.1711
600us Clients 1 2 4 8 12 16 32
Energy/Joules 4915 (0.51%) 4912 (29.98%) 3506 (-1.71%) 4907 (-4.85% ) 5011 (-10.69%) 5672 (-12.74%) 8141 (-0.27%)
Throughput/(MB/s) 348 (6.42%) 284 (70.06%) 220 (0.00% ) 518 (-10.23%) 712 (-8.13% ) 854 (-8.96% ) 1475 (5.58% )
PPW 0.0708(5.99%) 0.0578(31.07%) 0.0627(1.79% ) 0.1055(-5.64% ) 0.142(2.82% ) 0.1505(4.30% ) 0.1811(5.84% )
============= =================== ============== =============== ============== =============== ============== =============== ===============
3.Hackbench(less time is better)
============= =========================== ==========================
hackbench governor:schedutil
============= =========================== ==========================
Trans Delay Process Mode Ave time(s) Thread Mode Ave time(s)
1000us 14.484 14.484
600us 14.418(-0.46%) 15.41(+6.39%)
============= =========================== ==========================
4.Perf_sched_bench(less time is better)
============= =================== ============== ============== ============== =============== =============== =============
Trans Delay perf_sched_bench governor:schedutil
============= =================== ============== ============== ============== =============== =============== =============
1000us Groups 1 2 4 8 12 24
AveTime(s) 1.64 2.851 5.878 11.636 16.093 26.395
600us Groups 1 2 4 8 12 24
AveTime(s) 1.69(3.05%) 2.845(-0.21%) 5.843(-0.60%) 11.576(-0.52%) 16.092(-0.01%) 26.32(-0.28%)
============= ================== ============== ============== ============== =============== =============== ==============
5.Sysbench(higher is better)
============= ================== ============== ================= ============== ================ =============== =================
Sysbench governor:schedutil
============= ================== ============== ================= ============== ================ =============== =================
1000us Thread 1 2 4 8 12 24
Ave events 6020.98 12273.39 24119.82 46171.57 47074.37 47831.72
600us Thread 1 2 4 8 12 24
Ave events 6154.82(2.22%) 12271.63(-0.01%) 24392.5(1.13%) 46117.64(-0.12%) 46852.19(-0.47%) 47678.92(-0.32%)
============= ================== ============== ================= ============== ================ =============== =================
In conclusion, a shorter transition delay
of cpu clock will make a quite positive effect to improve PPW on Dbench test,
in the meanwhile , keep stable performance on Tbench,
Hackbench, Perf_sched_bench and Sysbench.
Signed-off-by: Xiaojian Du <Xiaojian.Du@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
---
drivers/cpufreq/amd-pstate.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 2015c9fcc3c9..8c8594f67af6 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -50,6 +50,7 @@
#define AMD_PSTATE_TRANSITION_LATENCY 20000
#define AMD_PSTATE_TRANSITION_DELAY 1000
+#define AMD_PSTATE_FAST_CPPC_TRANSITION_DELAY 600
#define AMD_PSTATE_PREFCORE_THRESHOLD 166
/*
@@ -868,7 +869,11 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
}
policy->cpuinfo.transition_latency = AMD_PSTATE_TRANSITION_LATENCY;
- policy->transition_delay_us = AMD_PSTATE_TRANSITION_DELAY;
+
+ if (cpu_feature_enabled(X86_FEATURE_FAST_CPPC))
+ policy->transition_delay_us = AMD_PSTATE_FAST_CPPC_TRANSITION_DELAY;
+ else
+ policy->transition_delay_us = AMD_PSTATE_TRANSITION_DELAY;
policy->min = min_freq;
policy->max = max_freq;
--
2.34.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* RE: [PATCH 2/2] cpufreq: amd-pstate: change cpu freq transition delay for some models
2024-04-29 7:03 ` [PATCH 2/2] cpufreq: amd-pstate: change cpu freq transition delay for some models Xiaojian Du
@ 2024-05-11 6:54 ` Yuan, Perry
2024-05-22 16:46 ` Mario Limonciello
1 sibling, 0 replies; 4+ messages in thread
From: Yuan, Perry @ 2024-05-11 6:54 UTC (permalink / raw)
To: Du, Xiaojian, linux-kernel, linux-pm
Cc: tglx, mingo, bp, dave.hansen, hpa, daniel.sneddon, jpoimboe,
pawan.kumar.gupta, Das1, Sandipan, kai.huang, x86, Huang, Ray,
rafael, Limonciello, Mario
[AMD Official Use Only - General]
> -----Original Message-----
> From: Du, Xiaojian <Xiaojian.Du@amd.com>
> Sent: Monday, April 29, 2024 3:03 PM
> To: linux-kernel@vger.kernel.org; linux-pm@vger.kernel.org
> Cc: tglx@linutronix.de; mingo@redhat.com; bp@alien8.de;
> dave.hansen@linux.intel.com; hpa@zytor.com;
> daniel.sneddon@linux.intel.com; jpoimboe@kernel.org;
> pawan.kumar.gupta@linux.intel.com; Das1, Sandipan
> <Sandipan.Das@amd.com>; kai.huang@intel.com; Yuan, Perry
> <Perry.Yuan@amd.com>; x86@kernel.org; Huang, Ray
> <Ray.Huang@amd.com>; rafael@kernel.org; Du, Xiaojian
> <Xiaojian.Du@amd.com>; Limonciello, Mario <Mario.Limonciello@amd.com>
> Subject: [PATCH 2/2] cpufreq: amd-pstate: change cpu freq transition delay
> for some models
>
> Some of AMD ZEN4 APU/CPU have support for adjusting the CPU core clock
> more quickly and presicely according to CPU work loading.
> This is advertised by the Fast CPPC x86 feature.
> This change will only be effective in the *passive mode* of AMD pstate
> driver. From the test results of different transition delay values, 600us is
> chosen to make a balance between performance and power consumption.
>
> Some test results on AMD Ryzen 7840HS(Phoenix) APU:
>
> 1. Tbench
> (Energy less is better, Throughput more is better, PPW--Performance per
> Watt more is better) ============= ===================
> ============== =============== ==============
> =============== ============== ===============
> ===============
> Trans Delay Tbench governor:schedutil, 3-iterations average
> ============= =================== ==============
> =============== ============== ===============
> ============== =============== ===============
> 1000us Clients 1 2 4 8 12 16
> 32
> Energy/Joules 2010 2804 8768 17171 16170
> 15132 15027
> Throughput/(MB/s) 114 259 1041 3010 3135
> 4851 4605
> PPW 0.0567 0.0923 0.1187 0.1752 0.1938
> 0.3205 0.3064
> 600us Clients 1 2 4 8 12 16 32
> Energy/Joules 2115 (5.22%) 2388 (-14.84%) 10700(22.03%) 16716
> (-2.65%) 15939 (-1.43%) 15053 (-0.52%) 15083 (0.37% )
> Throughput/(MB/s) 122 (7.02%) 234 (-9.65% ) 1188 (14.12%) 3003
> (-0.23%) 3143 (0.26% ) 4842 (-0.19%) 4603 (-0.04%)
> PPW 0.0576(1.59%) 0.0979(6.07% ) 0.111(-6.49%)
> 0.1796(2.51% ) 0.1971(1.70% ) 0.3216(0.34% ) 0.3051(-0.42%)
> ============= =================== ==============
> ================ ============= ===============
> ============== =============== ===============
>
> 2.Dbench
> (Energy less is better, Throughput more is better, PPW--Performance per
> Watt more is better) ============= ===================
> ============== =============== ==============
> =============== ============== ===============
> ===============
> Trans Delay Dbench governor:schedutil, 3-iterations average
> ============= =================== ==============
> =============== ============== ===============
> ============== =============== ===============
> 1000us Clients 1 2 4 8 12 16
> 32
> Energy/Joules 4890 3779 3567 5157 5611
> 6500 8163
> Throughput/(MB/s) 327 167 220 577 775
> 938 1397
> PPW 0.0668 0.0441 0.0616 0.1118 0.1381
> 0.1443 0.1711
> 600us Clients 1 2 4 8 12 16 32
> Energy/Joules 4915 (0.51%) 4912 (29.98%) 3506 (-1.71%) 4907 (-
> 4.85% ) 5011 (-10.69%) 5672 (-12.74%) 8141 (-0.27%)
> Throughput/(MB/s) 348 (6.42%) 284 (70.06%) 220 (0.00% ) 518 (-
> 10.23%) 712 (-8.13% ) 854 (-8.96% ) 1475 (5.58% )
> PPW 0.0708(5.99%) 0.0578(31.07%) 0.0627(1.79% ) 0.1055(-
> 5.64% ) 0.142(2.82% ) 0.1505(4.30% ) 0.1811(5.84% )
> ============= =================== ==============
> =============== ============== ===============
> ============== =============== ===============
>
> 3.Hackbench(less time is better)
> ============= ===========================
> ==========================
> hackbench governor:schedutil
> ============= ===========================
> ==========================
> Trans Delay Process Mode Ave time(s) Thread Mode Ave time(s)
> 1000us 14.484 14.484
> 600us 14.418(-0.46%) 15.41(+6.39%)
> ============= ===========================
> ==========================
>
> 4.Perf_sched_bench(less time is better)
> ============= =================== ==============
> ============== ============== ===============
> =============== =============
> Trans Delay perf_sched_bench governor:schedutil
> ============= =================== ==============
> ============== ============== ===============
> =============== =============
> 1000us Groups 1 2 4 8 12 24
> AveTime(s) 1.64 2.851 5.878 11.636 16.093
> 26.395
> 600us Groups 1 2 4 8 12 24
> AveTime(s) 1.69(3.05%) 2.845(-0.21%) 5.843(-0.60%) 11.576(-
> 0.52%) 16.092(-0.01%) 26.32(-0.28%)
> ============= ================== ==============
> ============== ============== ===============
> =============== ==============
>
> 5.Sysbench(higher is better)
> ============= ================== ==============
> ================= ============== ================
> =============== =================
> Sysbench governor:schedutil
> ============= ================== ==============
> ================= ============== ================
> =============== =================
> 1000us Thread 1 2 4 8 12 24
> Ave events 6020.98 12273.39 24119.82 46171.57
> 47074.37 47831.72
> 600us Thread 1 2 4 8 12 24
> Ave events 6154.82(2.22%) 12271.63(-0.01%) 24392.5(1.13%)
> 46117.64(-0.12%) 46852.19(-0.47%) 47678.92(-0.32%)
> ============= ================== ==============
> ================= ============== ================
> =============== =================
>
> In conclusion, a shorter transition delay of cpu clock will make a quite positive
> effect to improve PPW on Dbench test, in the meanwhile , keep stable
> performance on Tbench, Hackbench, Perf_sched_bench and Sysbench.
>
> Signed-off-by: Xiaojian Du <Xiaojian.Du@amd.com>
> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
> drivers/cpufreq/amd-pstate.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 2015c9fcc3c9..8c8594f67af6 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -50,6 +50,7 @@
>
> #define AMD_PSTATE_TRANSITION_LATENCY 20000
> #define AMD_PSTATE_TRANSITION_DELAY 1000
> +#define AMD_PSTATE_FAST_CPPC_TRANSITION_DELAY 600
> #define AMD_PSTATE_PREFCORE_THRESHOLD 166
>
> /*
> @@ -868,7 +869,11 @@ static int amd_pstate_cpu_init(struct cpufreq_policy
> *policy)
> }
>
> policy->cpuinfo.transition_latency =
> AMD_PSTATE_TRANSITION_LATENCY;
> - policy->transition_delay_us = AMD_PSTATE_TRANSITION_DELAY;
> +
> + if (cpu_feature_enabled(X86_FEATURE_FAST_CPPC))
> + policy->transition_delay_us =
> AMD_PSTATE_FAST_CPPC_TRANSITION_DELAY;
> + else
> + policy->transition_delay_us =
> AMD_PSTATE_TRANSITION_DELAY;
>
> policy->min = min_freq;
> policy->max = max_freq;
> --
> 2.34.1
LGTM
Reviewed-by: Perry Yuan <perry.yuan@amd.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 2/2] cpufreq: amd-pstate: change cpu freq transition delay for some models
2024-04-29 7:03 ` [PATCH 2/2] cpufreq: amd-pstate: change cpu freq transition delay for some models Xiaojian Du
2024-05-11 6:54 ` Yuan, Perry
@ 2024-05-22 16:46 ` Mario Limonciello
1 sibling, 0 replies; 4+ messages in thread
From: Mario Limonciello @ 2024-05-22 16:46 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: tglx, mingo, bp, dave.hansen, hpa, daniel.sneddon, jpoimboe,
pawan.kumar.gupta, sandipan.das, kai.huang, perry.yuan, x86,
ray.huang, Xiaojian Du, linux-kernel, linux-pm
On 4/29/2024 02:03, Xiaojian Du wrote:
> Some of AMD ZEN4 APU/CPU have support for adjusting the CPU core
> clock more quickly and presicely according to CPU work loading.
> This is advertised by the Fast CPPC x86 feature.
> This change will only be effective in the *passive mode* of
> AMD pstate driver. From the test results of different
> transition delay values, 600us is chosen to make a balance
> between performance and power consumption.
>
> Some test results on AMD Ryzen 7840HS(Phoenix) APU:
>
> 1. Tbench
> (Energy less is better, Throughput more is better,
> PPW--Performance per Watt more is better)
> ============= =================== ============== =============== ============== =============== ============== =============== ===============
> Trans Delay Tbench governor:schedutil, 3-iterations average
> ============= =================== ============== =============== ============== =============== ============== =============== ===============
> 1000us Clients 1 2 4 8 12 16 32
> Energy/Joules 2010 2804 8768 17171 16170 15132 15027
> Throughput/(MB/s) 114 259 1041 3010 3135 4851 4605
> PPW 0.0567 0.0923 0.1187 0.1752 0.1938 0.3205 0.3064
> 600us Clients 1 2 4 8 12 16 32
> Energy/Joules 2115 (5.22%) 2388 (-14.84%) 10700(22.03%) 16716 (-2.65%) 15939 (-1.43%) 15053 (-0.52%) 15083 (0.37% )
> Throughput/(MB/s) 122 (7.02%) 234 (-9.65% ) 1188 (14.12%) 3003 (-0.23%) 3143 (0.26% ) 4842 (-0.19%) 4603 (-0.04%)
> PPW 0.0576(1.59%) 0.0979(6.07% ) 0.111(-6.49%) 0.1796(2.51% ) 0.1971(1.70% ) 0.3216(0.34% ) 0.3051(-0.42%)
> ============= =================== ============== ================ ============= =============== ============== =============== ===============
>
> 2.Dbench
> (Energy less is better, Throughput more is better,
> PPW--Performance per Watt more is better)
> ============= =================== ============== =============== ============== =============== ============== =============== ===============
> Trans Delay Dbench governor:schedutil, 3-iterations average
> ============= =================== ============== =============== ============== =============== ============== =============== ===============
> 1000us Clients 1 2 4 8 12 16 32
> Energy/Joules 4890 3779 3567 5157 5611 6500 8163
> Throughput/(MB/s) 327 167 220 577 775 938 1397
> PPW 0.0668 0.0441 0.0616 0.1118 0.1381 0.1443 0.1711
> 600us Clients 1 2 4 8 12 16 32
> Energy/Joules 4915 (0.51%) 4912 (29.98%) 3506 (-1.71%) 4907 (-4.85% ) 5011 (-10.69%) 5672 (-12.74%) 8141 (-0.27%)
> Throughput/(MB/s) 348 (6.42%) 284 (70.06%) 220 (0.00% ) 518 (-10.23%) 712 (-8.13% ) 854 (-8.96% ) 1475 (5.58% )
> PPW 0.0708(5.99%) 0.0578(31.07%) 0.0627(1.79% ) 0.1055(-5.64% ) 0.142(2.82% ) 0.1505(4.30% ) 0.1811(5.84% )
> ============= =================== ============== =============== ============== =============== ============== =============== ===============
>
> 3.Hackbench(less time is better)
> ============= =========================== ==========================
> hackbench governor:schedutil
> ============= =========================== ==========================
> Trans Delay Process Mode Ave time(s) Thread Mode Ave time(s)
> 1000us 14.484 14.484
> 600us 14.418(-0.46%) 15.41(+6.39%)
> ============= =========================== ==========================
>
> 4.Perf_sched_bench(less time is better)
> ============= =================== ============== ============== ============== =============== =============== =============
> Trans Delay perf_sched_bench governor:schedutil
> ============= =================== ============== ============== ============== =============== =============== =============
> 1000us Groups 1 2 4 8 12 24
> AveTime(s) 1.64 2.851 5.878 11.636 16.093 26.395
> 600us Groups 1 2 4 8 12 24
> AveTime(s) 1.69(3.05%) 2.845(-0.21%) 5.843(-0.60%) 11.576(-0.52%) 16.092(-0.01%) 26.32(-0.28%)
> ============= ================== ============== ============== ============== =============== =============== ==============
>
> 5.Sysbench(higher is better)
> ============= ================== ============== ================= ============== ================ =============== =================
> Sysbench governor:schedutil
> ============= ================== ============== ================= ============== ================ =============== =================
> 1000us Thread 1 2 4 8 12 24
> Ave events 6020.98 12273.39 24119.82 46171.57 47074.37 47831.72
> 600us Thread 1 2 4 8 12 24
> Ave events 6154.82(2.22%) 12271.63(-0.01%) 24392.5(1.13%) 46117.64(-0.12%) 46852.19(-0.47%) 47678.92(-0.32%)
> ============= ================== ============== ================= ============== ================ =============== =================
>
> In conclusion, a shorter transition delay
> of cpu clock will make a quite positive effect to improve PPW on Dbench test,
> in the meanwhile , keep stable performance on Tbench,
> Hackbench, Perf_sched_bench and Sysbench.
>
> Signed-off-by: Xiaojian Du <Xiaojian.Du@amd.com>
> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Rafael,
You can swap my R-b for an A-b for when you pick this up after merge window.
Thx!
Acked-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
> drivers/cpufreq/amd-pstate.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 2015c9fcc3c9..8c8594f67af6 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -50,6 +50,7 @@
>
> #define AMD_PSTATE_TRANSITION_LATENCY 20000
> #define AMD_PSTATE_TRANSITION_DELAY 1000
> +#define AMD_PSTATE_FAST_CPPC_TRANSITION_DELAY 600
> #define AMD_PSTATE_PREFCORE_THRESHOLD 166
>
> /*
> @@ -868,7 +869,11 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
> }
>
> policy->cpuinfo.transition_latency = AMD_PSTATE_TRANSITION_LATENCY;
> - policy->transition_delay_us = AMD_PSTATE_TRANSITION_DELAY;
> +
> + if (cpu_feature_enabled(X86_FEATURE_FAST_CPPC))
> + policy->transition_delay_us = AMD_PSTATE_FAST_CPPC_TRANSITION_DELAY;
> + else
> + policy->transition_delay_us = AMD_PSTATE_TRANSITION_DELAY;
>
> policy->min = min_freq;
> policy->max = max_freq;
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-05-22 16:46 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-04-29 7:03 [PATCH 1/2] x86/cpufeatures: Add AMD FAST CPPC feature flag Xiaojian Du
2024-04-29 7:03 ` [PATCH 2/2] cpufreq: amd-pstate: change cpu freq transition delay for some models Xiaojian Du
2024-05-11 6:54 ` Yuan, Perry
2024-05-22 16:46 ` Mario Limonciello
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