On Fri, Nov 15, 2019 at 10:51 PM Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx> wrote: > > Added documentation to configure servers to use Intel(R) Speed > Select Technology using intel-speed-select tool. > Acked-by: Andriy Shevchenko <andy.shevchenko@xxxxxxxxx> > Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx> > --- > .../admin-guide/pm/intel-speed-select.rst | 934 ++++++++++++++++++ > .../admin-guide/pm/working-state.rst | 1 + > 2 files changed, 935 insertions(+) > create mode 100644 Documentation/admin-guide/pm/intel-speed-select.rst > > diff --git a/Documentation/admin-guide/pm/intel-speed-select.rst b/Documentation/admin-guide/pm/intel-speed-select.rst > new file mode 100644 > index 000000000000..c2ce57ebc268 > --- /dev/null > +++ b/Documentation/admin-guide/pm/intel-speed-select.rst > @@ -0,0 +1,934 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +========================================================= > +Intel® Speed Select Technology (Intel® SST) : User Guide > +========================================================= > + > +The Intel® Speed Select Technology (Intel® SST) provides a powerful new > +collection of features that give more granular control over CPU performance. > +With Intel® SST, one server can be configured for power and performance for a > +variety of diverse workload requirements. > + > +Refer to the links below for an overview of the technology: > + > +- https://www.intel.com/content/www/us/en/architecture-and-technology/speed-select-technology-article.html > +- https://builders.intel.com/docs/networkbuilders/intel-speed-select-technology-base-frequency-enhancing-performance.pdf > + > +These capabilities are further enhanced in some of the newer generations of > +server platforms where these features can be enumerated and controlled > +dynamically without pre-configuring via BIOS setup options. This dynamic > +configuration is done via mailbox commands to the hardware. One way to enumerate > +and configure these features is by using the Intel® Speed Select utility. > + > +This document explains how to use the Intel® Speed Select tool to enumerate and > +control Intel® SST features. This document gives example commands and explains > +how these commands change the power and performance profile of the system under > +test. Using this tool as an example, customers can replicate the messaging > +implemented in the tool in their production software. > + > + > +intel-speed-select configuration tool > +------------------------------------- > +Most Linux distribution packages include the "intel-speed-select" tool. If not, > +it can be built by downloading the Linux kernel tree from kernel.org. Once > +downloaded, the tool can be built without building the full kernel. > + > +From the kernel tree, run the following commands: > + > +# cd tools/power/x86/intel-speed-select/ > + > +# make > + > +# make install > + > +**Getting Help** > + > +To get help with the tool, execute the command below: > + > +#intel-speed-select --help > + > +The top-level help describes arguments and features. Notice that there is a > +multi-level help structure in the tool. For example: > + > +#intel-speed-select perf-profile --help > + > +This brings help for the feature "perf-profile" > + > +#intel-speed-select perf-profile info --help > + > +This brings help for the command "info". > + > + > +Intel® Speed Select Technology - Performance Profile (Intel® SST-PP) > +---------------------------------------- > + > +This feature allows configuration of a server dynamically based on workload > +performance requirements. This helps users during deployment as they do not have > +to choose a specific server configuration statically. This Intel® Speed Select > +Technology - Performance Profile (Intel® SST-PP) feature introduces a mechanism > +that allows multiple optimized performance profiles per system. Each profile > +defines a set of CPUs that need to be online and rest offline to sustain a > +guaranteed base frequency. Once the user issues a command to use a specific > +performance profile and meet CPU online/offline requirement, the user can expect > +a change in the base frequency dynamically. This feature is called > +"perf-profile" when using the Intel® Speed Select tool. > + > +**Number or performance levels** > + > +There can be multiple performance profiles on a system. To get the number of > +profiles, execute the command below: > + > +#intel-speed-select perf-profile get-config-levels > + package-0 > + die-0 > + cpu-0 > + get-config-levels:4 > + package-1 > + die-0 > + cpu-14 > + get-config-levels:4 > + > +On this system under test, there are 4 performance profiles in addition to the > +base performance profile (which is performance level 0). > + > +**Lock/Unlock status** > + > +Even if there are multiple performance profiles, it is possible that that they > +are locked. If they are locked, users cannot issue a command to change the > +performance state. It is possible that there is a BIOS setup to unlock or check > +with your system vendor. > + > +To check if the system is locked, execute the following command: > + > +#intel-speed-select perf-profile get-lock-status > + package-0 > + die-0 > + cpu-0 > + get-lock-status:0 > + package-1 > + die-0 > + cpu-14 > + get-lock-status:0 > + > +In this case, lock status is 0, which means that the system is unlocked. > + > +**Properties of a performance level** > + > +To get properties of a specific performance level (For example for the level 0, below), execute the command below: > + > +#intel-speed-select perf-profile info -l 0 > + package-0 > + die-0 > + cpu-0 > + perf-profile-level-0 > + cpu-count:28 > + > + enable-cpu-mask:000003ff,f0003fff > + > + enable-cpu-list:0,1,2,3,4,5,6,7,8,9,10,11,12,13,28,29,30,31,32,33,34,35,36,37,38,39,40,41 > + > + thermal-design-power-ratio:26 > + > + base-frequency(MHz):2600 > + > + speed-select-turbo-freq:disabled > + > + speed-select-base-freq:disabled > + ... > + ... > + > +Here -l option is used to specify a performance level. > + > +If the option -l is omitted, then this command will print information about all > +the performance levels. The above command is printing properties of the > +performance level 0. > + > +For this performance profile, the list of CPUs displayed by the > +"enable-cpu-mask/enable-cpu-list" at the max can be "online." When that > +condition is met, then base frequency of 2600 MHz can be maintained. To > +understand more, execute "intel-speed-select perf-profile info" for performance > +level 4. > + > +#intel-speed-select perf-profile info -l 4 > + package-0 > + die-0 > + cpu-0 > + perf-profile-level-4 > + cpu-count:28 > + > + enable-cpu-mask:000000fa,f0000faf > + > + enable-cpu-list:0,1,2,3,5,7,8,9,10,11,28,29,30,31,33,35,36,37,38,39 > + > + thermal-design-power-ratio:28 > + > + base-frequency(MHz):2800 > + > + speed-select-turbo-freq:disabled > + > + speed-select-base-freq:unsupported > + ... > + ... > + > +There are fewer CPUs in the “enable-cpu-mask/enable-cpu-list.” Consequently, if > +the user only keeps these CPUs online and the rest "offline," then the base > +frequency is increased to 2.8 GHz compared to 2.6 GHz at performance level 0. > + > +**Get current performance level** > + > +To get the current performance level, execute: > + > +# intel-speed-select perf-profile get-config-current-level > + package-0 > + die-0 > + cpu-0 > + get-config-current_level:0 > + > +First verify that the base_frequency displayed by the cpufreq sysfs is correct: > + > +# cat /sys/devices/system/cpu/cpu0/cpufreq/base_frequency > + > +2600000 > + > +This matches the base-frequency (MHz) field value displayed from the > +"perf-profile info" command for performance level 0(cpufreq frequency is in > +KHz). > + > +To check if the average frequency is equal to the base frequency for a 100% busy > +workload, disable turbo: > + > +# echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo > + > +Then runs a busy workload on all CPUs, for example: > + > +#stress -c 64 > + > +To verify the base frequency, run turbostat: > + > +#turbostat -c 0-13 --show Package,Core,CPU,Bzy_MHz -i 1 > + > +======= ==== ===== ========= > +Package Core CPU Bzy_MHz > +======= ==== ===== ========= > + - - 2600 > +0 0 0 2600 > +0 1 1 2600 > +0 2 2 2600 > +0 3 3 2600 > +0 4 4 2600 > +. . . . > +. . . . > +======= ==== ===== ========= > + > +**Changing performance level** > + > +To the change the performance level to 4, execute: > + > +#intel-speed-select -d perf-profile set-config-level -l 4 -o > + package-0 > + die-0 > + cpu-0 > + perf-profile > + set_tdp_level:success > + > +In the command above, "-o" is optional. If it is specified, then it will also > +offline CPUs which are not present in the enable_cpu_mask for this performance > +level. > + > +Now if the base_frequency is checked: > + > +#cat /sys/devices/system/cpu/cpu0/cpufreq/base_frequency > + > +2800000 > + > +Which shows that the base frequency now increased from 2600 MHz at performance > +level 0 to 2800 MHz at performance level 4. As a result, any workload, which can > +use fewer CPUs, can see a boost of 200 MHz compared to performance level 0. > + > +**Check presence of other Intel® SST features** > + > +Each of the performance profiles also specifies weather there is support of > +other two Intel® SST features (Intel® Speed Select Technology - Base Frequency > +(Intel® SST-BF) and Intel® Speed Select Technology - Turbo Frequency (Intel® > +SST-TF)). > + > +For example, from the output of "perf-profile info" above, for level 0 and level > +4: > + > +For level 0: > + speed-select-turbo-freq:disabled > + > + speed-select-base-freq:disabled > + > +For level 4: > + > + speed-select-turbo-freq:disabled > + > + speed-select-base-freq:unsupported > + > +Given these results, the “speed-select-base-freq” (Intel® SST-BF) in level 4 > +changed from "disabled" to "unsupported" compared to performance level 0. > + > +This means that at performance level 4, the "speed-select-base-freq" feature is > +not supported. However, at performance level 0, this feature is "supported", but > +currently "disabled", meaning the user has not activated this feature. Whereas > +"speed-select-turbo-freq" (Intel® SST-TF) is supported at both performance > +levels, but currently not activated by the user. > + > +The Intel® SST-BF and the Intel® SST-TF features are built on a foundation > +technology called Intel® Speed Select Technology - Core Power (Intel® SST-CP). > +The platform firmware enables this feature when Intel® SST-BF or Intel® SST-TF > +is supported on a platform. > + > +Intel® Speed Select Technology – Core Power (Intel® SST-CP) > +---------------------------------------- > + > +Intel® Speed Select Technology – Core Power (Intel® SST-CP) is an interface that > +allows users to define per core priority. This defines a mechanism to distribute > +power among cores when there is a power constrained scenario. This defines a > +class of service (CLOS) configuration. > + > +The user can configure up to 4 class of service configurations. Each CLOS group > +configuration allows definitions of parameters, which affects how the frequency > +can be limited and power is distributed. Each CPU core can be tied to a class of > +service and hence an associated priority. The granularity is at core level not > +at per CPU level. > + > +**Enable CLOS based prioritization** > + > +To use CLOS based prioritization feature, firmware must be informed to enable > +and use a priority type. There is a default per platform priority type, which > +can be changed with optional command line parameter. > + > +To enable and check the options, execute: > + > +# intel-speed-select core-power enable --help > + > +Intel(R) Speed Select Technology > + > +Enable core-power for a package/die > + Clos Enable: Specify priority type with [--priority|-p] > + 0: Proportional, 1: Ordered > + > +There are two types of priority types: > + > +- Ordered > +Priority for ordered throttling is defined based on the index of the assigned > +CLOS group. Where CLOS0 gets highest priority (throttled last). > + > +Priority order is: > +CLOS0 > CLOS1 > CLOS2 > CLOS3. > + > +- Proportional > +When proportional priority is used, there is an additional parameter called > +frequency_weight, which can be specified per CLOS group. The goal of > +proportional priority is to provide each core with the requested min., then > +distribute all remaining (excess/deficit) budgets in proportion to a defined > +weight. This proportional priority can be configured using "core-power config" > +command. > + > +To enable with the platform default priority type, execute: > + > +# intel-speed-select core-power enable > + package-0 > + die-0 > + cpu-0 > + core-power > + enable:success > + package-1 > + die-0 > + cpu-6 > + core-power > + enable:success > + > +The scope of this enable is per package or die scoped when a package contains > +multiple dies. To check if CLOS is enabled and get priority type, "core-power > +info" command can be used. For example to check the status of core-power feature > +on CPU 0, execute: > + > +#intel-speed-select -c 0 core-power info > + package-0 > + die-0 > + cpu-0 > + core-power > + enable-status:1 > + priority-type:0 > + > + > +**Configuring CLOS groups** > + > +Each CLOS group has its own attributes including min, max, freq_weight and > +desired. These parameters can be configured with "core-power config" command. > +Defaults will be used if user skips setting a parameter except clos id, which is > +mandatory. > + > +#intel-speed-select core-power config --help > + > +Intel(R) Speed Select Technology > + > +Set core-power configuration for one of the four clos ids > + Specify targeted clos id with [--clos|-c] > + > + Specify clos Proportional Priority [--weight|-w] > + > + Specify clos min in MHz with [--min|-n] > + > + Specify clos max in MHz with [--max|-m] > + > + Specify clos desired in MHz with [--desired|-d] > + > +For example: > +#intel-speed-select core-power config -c 0 > + > +Intel(R) Speed Select Technology > + > +clos epp is not specified, default: 0 > + > +clos frequency weight is not specified, default: 0 > + > +clos min is not specified, default: 0 MHz > + > +clos max is not specified, default: 25500 MHz > + > +clos desired is not specified, default: 0 > + package-0 > + die-0 > + cpu-0 > + core-power > + config:success > + package-1 > + die-0 > + cpu-6 > + core-power > + config:success > + > +The user has the option to change defaults. For example, the user can change the > +"min" and set the base frequency to always get guaranteed base frequency. > + > +**Get the current CLOS configuration** > + > +To check the current configuration, "core-power get-config" can be used. For > +example, to get the configuration of CLOS 0: > + > +#intel-speed-select core-power get-config -c 0 > + package-0 > + die-0 > + cpu-0 > + core-power > + > + clos:0 > + > + epp:0 > + > + clos-proportional-priority:0 > + > + clos-min:0 MHz > + > + clos-max:25500 MHz > + > + clos-desired:0 > + > + package-1 > + die-0 > + cpu-6 > + core-power > + clos:0 > + > + epp:0 > + > + clos-proportional-priority:0 > + > + clos-min:0 MHz > + > + clos-max:25500 MHz > + > + clos-desired:0 > + > +**Associating a CPU with a CLOS group** > + > +To associate a CPU to a CLOS group "core-power assoc" command can be used. > + > +# intel-speed-select core-power assoc --help > +Associate a clos id to a CPU > + Specify targeted clos id with [--clos|-c] > + > + > +For example to associate CPU 10 to CLOS group 3, execute: > + > +#intel-speed-select -c 10 core-power assoc -c 3 > + package-1 > + die-0 > + cpu-10 > + core-power > + assoc:success > + > +Once a CPU is associated, its sibling CPUs are also associated to a CLOS group. > +Once associated, avoid changing Linux “cpufreq” subsystem scaling frequency > +limits. > + > +To check the existing association for a CPU, "core-power get-assoc" command can > +be used. For example, to get association of CPU 10, execute: > + > +#intel-speed-select -c 10 core-power get-assoc > + package-1 > + die-0 > + cpu-10 > + get-assoc > + clos:3 > + > +This shows that CPU 10 is part of a CLOS group 3. > + > + > +**Disable CLOS based prioritization** > + > +To disable, execute: > + > +# intel-speed-select core-power disable > + > +Some features like Intel® SST-TF can only be enabled when CLOS based prioritization > +is enabled. For this reason, disabling while Intel® SST-TF is enabled can cause > +Intel® SST-TF to fail. This will cause the "disable" command to display an error > +if Intel® SST-TF is already enabled. In turn, to disable, the Intel® SST-TF > +feature must be disabled first. > + > +Intel® Speed Select Technology - Base Frequency (Intel® SST-BF) > +---------------------------------- > + > +The Intel® Speed Select Technology - Base Frequency (Intel® SST-BF) feature lets > +the user control base frequency. If some critical workload threads demand > +constant high guaranteed performance, then this feature can be used to execute > +the thread at higher base frequency on specific sets of CPUs (high priority > +CPUs) at the cost of lower base frequency (low priority CPUs) on other CPUs. > +This feature does not require offline of the low priority CPUs. > + > +The support of Intel® SST-BF depends on the Intel® Speed Select Technology - > +Performance Profile (Intel® SST-PP) performance level configuration. It is > +possible that only certain performance levels support Intel® SST-BF. It is also > +possible that only base performance level (level = 0) has support of Intel® > +SST-BF. Consequently, first select the desired performance level to enable this > +feature. > + > +In the system under test here, Intel® SST-BF is supported at the base > +performance level 0, but currently disabled. > + > +#intel-speed-select -c 0 perf-profile info -l 0 > + package-0 > + die-0 > + cpu-0 > + perf-profile-level-0 > + ... > + ... > + speed-select-base-freq:disabled > + > + ... > + ... > + > +Before enabling Intel® SST-BF and measuring its impact on a workload > +performance, execute some workload and measure performance and get a baseline > +performance to compare against. > + > +Here the user wants more guaranteed performance. For this reason, it is likely > +that turbo is disabled. To disable turbo, execute: > + > +#echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo > + > +Based on the output of the "intel-speed-select perf-profile info -l 0" base > +frequency of guaranteed frequency 2600 MHz. > + > + > +**Measure baseline performance for comparison** > + > +To compare, pick a multi-threaded workload where each thread can be scheduled on > +separate CPUs. "Hackbench pipe" test is a good example on how to improve > +performance using Intel® SST-BF. > + > +Below, the workload is measuring average scheduler wakeup latency, so a lower > +number means better performance: > + > +# taskset -c 3,4 perf bench -r 100 sched pipe > + > +# Running 'sched/pipe' benchmark: > + > +# Executed 1000000 pipe operations between two processes > + > + Total time: 6.102 [sec] > + > + 6.102445 usecs/op > + > + 163868 ops/sec > + > +While running the above test, if we take turbostat output, it will show us that > +2 of the CPUs are busy and reaching max. frequency (which would be the base > +frequency as the turbo is disabled). > + > +======= ==== ==== ======= > +Package Core CPU Bzy_MHz > +======= ==== ==== ======= > +0 0 0 1000 > +0 1 1 1005 > +0 2 2 1000 > +0 3 3 2600 > +0 4 4 2600 > +0 5 5 1000 > +0 6 6 1000 > +0 7 7 1005 > +0 8 8 1005 > +0 9 9 1000 > +0 10 10 1000 > +0 11 11 995 > +0 12 12 1000 > +0 13 13 1000 > +======= ==== ==== ======= > + > +From the above turbostat output, both CPU 3 and 4 are very busy and reaching > +full guaranteed frequency of 2600 MHz. > + > +**Intel® SST-BF Capabilities** > + > +To get capabilities of Intel® SST-BF for the current performance level 0, > +execute: > + > +#intel-speed-select base-freq info -l 0 > + package-0 > + die-0 > + cpu-0 > + speed-select-base-freq > + high-priority-base-frequency(MHz):3000 > + > + high-priority-cpu-mask:00000216,00002160 > + > + high-priority-cpu-list:5,6,8,13,33,34,36,41 > + > + low-priority-base-frequency(MHz):2400 > + > + tjunction-temperature(C):125 > + > + thermal-design-power(W):205 > + > +The above capabilities show that there are some CPUs on this system that can > +offer base frequency of 3000 MHz compared to the standard base frequency at this > +performance levels. Nevertheless, these CPUs are fixed, and they are presented > +via high-priority-cpu-list/high-priority-cpu-mask. But if this Intel® SST-BF > +feature is selected, the low priorities CPUs (which are not in > +high-priority-cpu-list) can only offer up to 2400 MHz. As a result, if this > +clipping of low priority CPUs is acceptable, then the user can enable Intel® > +SST-BF feature particularly for the above "sched pipe" workload since only two > +CPUs are used, they can be scheduled on high priority CPUs and can get boost of > +400 MHz. > + > +**Enable Intel® SST-BF** > + > +To enable Intel® SST-BF feature, execute: > + > +#intel-speed-select base-freq enable -a > + package-0 > + die-0 > + cpu-0 > + base-freq > + enable:success > + package-1 > + die-0 > + cpu-14 > + base-freq > + enable:success > + > +In this case, -a option is optional. This not only enables Intel® SST-BF, but it > +also adjusts the priority of cores using Intel® Speed Select Technology – Core > +Power (Intel® SST-CP) features. This option sets the minimum performance of each > +Intel® Speed Select Technology - Performance Profile (Intel® SST-PP) class to > +maximum performance so that the hardware will give maximum performance possible > +for each CPU. > + > +If -a option is not used, then the following steps are required before enabling > +Intel® SST-BF: > + > +- Discover Intel® SST-BF and note low and high priority base frequency > +- Note the high prioity CPU list > +- Enable CLOS using core-power feature set > +- Configure CLOS parameters. Use CLOS.min to set to minimum performance > +- Subscribe desired CPUs to CLOS groups > + > +With this configuration, if the same workload is executed by pinning the > +workload to high priority CPUs (CPU 5 and 6 in this case): > + > +#taskset -c 5,6 perf bench -r 100 sched pipe > + > +# Running 'sched/pipe' benchmark: > + > +# Executed 1000000 pipe operations between two processes > + > + Total time: 5.627 [sec] > + > + 5.627922 usecs/op > + 177685 ops/sec > + > +This way, by enabling Intel® SST-BF, the performance of this benchmark is > +improved (latency reduced) by 7.79%. From the turbostat output, it can be > +observed that the high priority CPUs reached 3000 MHz compared to 2600 MHz. > + > +======= ==== ==== ======= > +Package Core CPU Bzy_MHz > +======= ==== ==== ======= > +0 0 0 2151 > +0 1 1 2166 > +0 2 2 2175 > +0 3 3 2175 > +0 4 4 2175 > +0 5 5 3000 > +0 6 6 3000 > +0 7 7 2180 > +0 8 8 2662 > +0 9 9 2176 > +0 10 10 2175 > +0 11 11 2176 > +0 12 12 2176 > +0 13 13 2661 > +======= ==== ==== ======= > + > +**Disable Intel® SST-BF** > + > +To disable the Intel® SST-BF feature, execute: > + > +#intel-speed-select base-freq disable -a > + > + > +Intel® Speed Select Technology - Turbo Frequency (Intel® SST-TF) > +------------------------------------ > + > +This feature enables the ability to set different "All core turbo ratio limits" > +to cores based on the priority. By using this feature, some cores can be > +configured to get higher turbo frequency by designating them as high priority at > +the cost of lower or no turbo frequency on the low priority cores. > + > +For this reason, this feature is only useful when system is busy utilizing all > +CPUs, but the user wants some configurable option to get high performance on > +some CPUs. > + > +The support of Intel® Speed Select Technology - Turbo Frequency (Intel® SST-TF) > +depends on the Intel® Speed Select Technology - Performance Profile (Intel® > +SST-PP) performance level configuration. It is possible that only a certain > +performance level supports Intel® SST-TF. It is also possible that only the base > +performance level (level = 0) has the support of Intel® SST-TF. Hence, first > +select the desired performance level to enable this feature. > + > +In the system under test here, Intel® SST-TF is supported at the base > +performance level 0, but currently disabled. > + > +#intel-speed-select -c 0 perf-profile info -l 0 > + package-0 > + die-0 > + cpu-0 > + perf-profile-level-0 > + ... > + ... > + speed-select-turbo-freq:disabled > + > + ... > + ... > + > + > +To check if performance can be improved using Intel® SST-TF feature, get the turbo > +frequency properties with Intel® SST-TF enabled and compare to the base turbo > +capability of this system. > + > +**Get Base turbo capability** > + > +To get the base turbo capability of performance level 0, execute: > + > +#intel-speed-select perf-profile info -l 0 > + package-0 > + die-0 > + cpu-0 > + perf-profile-level-0 > + > + ... > + > + ... > + > + turbo-ratio-limits-sse > + bucket-0 > + core-count:2 > + > + max-turbo-frequency(MHz):3200 > + > + bucket-1 > + core-count:4 > + > + max-turbo-frequency(MHz):3100 > + bucket-2 > + core-count:6 > + > + max-turbo-frequency(MHz):3100 > + bucket-3 > + core-count:8 > + > + max-turbo-frequency(MHz):3100 > + bucket-4 > + core-count:10 > + > + max-turbo-frequency(MHz):3100 > + bucket-5 > + core-count:12 > + > + max-turbo-frequency(MHz):3100 > + bucket-6 > + core-count:14 > + > + max-turbo-frequency(MHz):3100 > + bucket-7 > + core-count:16 > + > + max-turbo-frequency(MHz):3100 > + > +Based on the data above, when all the CPUS are busy, the max. frequency of 3100 > +MHz can be achieved. If there is some busy workload on cpu 0 - 11 (e.g. stress) > +and on CPU 12 and 13, execute "hackbench pipe" workload: > + > +# taskset -c 12,13 perf bench -r 100 sched pipe > + > +# Running 'sched/pipe' benchmark: > + > +# Executed 1000000 pipe operations between two processes > + > + Total time: 5.705 [sec] > + > + 5.705488 usecs/op > + 175269 ops/sec > + > +======= ==== ==== ======= > +Package Core CPU Bzy_MHz > +======= ==== ==== ======= > +0 0 0 3000 > +0 1 1 3000 > +0 2 2 3000 > +0 3 3 3000 > +0 4 4 3000 > +0 5 5 3100 > +0 6 6 3100 > +0 7 7 3000 > +0 8 8 3100 > +0 9 9 3000 > +0 10 10 3000 > +0 11 11 3000 > +0 12 12 3100 > +0 13 13 3100 > +======= ==== ==== ======= > + > +Based on turbostat output, the performance is limited by frequency cap of 3100 > +MHz. To check if the hackbench performance can be improved for CPU 12 and CPU > +13, first check the capability of the Intel® SST-TF feature for this performance > +level. > + > +**Get Intel® SST-TF Capability** > + > +To get the capability, the "turbo-freq info" command can be used: > + > +#intel-speed-select turbo-freq info -l 0 > + speed-select-turbo-freq > + bucket-0 > + high-priority-cores-count:2 > + > + high-priority-max-frequency(MHz):3200 > + > + high-priority-max-avx2-frequency(MHz):3200 > + > + high-priority-max-avx512-frequency(MHz):3100 > + > + bucket-1 > + high-priority-cores-count:4 > + > + high-priority-max-frequency(MHz):3100 > + > + high-priority-max-avx2-frequency(MHz):3000 > + > + high-priority-max-avx512-frequency(MHz):2900 > + > + bucket-2 > + high-priority-cores-count:6 > + > + high-priority-max-frequency(MHz):3100 > + > + high-priority-max-avx2-frequency(MHz):3000 > + > + high-priority-max-avx512-frequency(MHz):2900 > + > + speed-select-turbo-freq-clip-frequencies > + low-priority-max-frequency(MHz):2600 > + > + low-priority-max-avx2-frequency(MHz):2400 > + > + low-priority-max-avx512-frequency(MHz):2100 > + > +Based on the output above, there is an Intel® SST-TF bucket for which there are > +two high priority cores. If only two high priority cores are set, then max. > +turbo frequency on those cores can be increased to 3200 MHz. This is 100 MHz > +more than the base turbo capability for all cores. > + > +In turn, for the hackbench workload, two CPUs can be set as high priority and > +rest as low priority. One side effect is that once enabled, the low priority > +cores will be clipped to a lower frequency of 2600 MHz. > + > +**Enable Intel® SST-TF** > + > +To enable Intel® SST-TF, execute: > + > +#intel-speed-select -c 12,13 turbo-freq enable -a > + > +Intel(R) Speed Select Technology > + package-0 > + die-0 > + cpu-12 > + turbo-freq > + enable:success > + package-0 > + die-0 > + cpu-13 > + turbo-freq > + enable:success > + > + package--1 > + die-0 > + cpu-63 > + turbo-freq --auto > + enable:success > + > +In this case, the option "-a" is optional. If set, it enables Intel® SST-TF > +feature and also sets the CPUs to high and and low priority using Intel® Speed > +Select Technology – Core Power (Intel® SST-CP) features. The CPU numbers passed > +with "-c" arguments are marked as high priority, including its siblings. > + > +If -a option is not used, then the following steps are required before enabling > +Intel® SST-TF: > + > +- Discover Intel® SST-TF and note buckets of high priority cores and maximum > +frequency > + > +- Enable CLOS using core-power feature set - Configure CLOS parameters > + > +- Subscribe desired CPUs to CLOS groups making sure that high priority cores are set to the maximum frequency > + > +If the same hackbench workload is executed, schedule hackbench threads on high > +priority CPUs: > + > +#taskset -c 12,13 perf bench -r 100 sched pipe > + > +# Running 'sched/pipe' benchmark: > + > +# Executed 1000000 pipe operations between two processes > + > + Total time: 5.510 [sec] > + > + 5.510165 usecs/op > + 180826 ops/sec > + > +This improved performance by around 3.3% improvement on a busy system. Here the > +turbostat output will show that the CPU 12 and CPU 13 are getting 100 MHz boost. > + > +======= ==== ==== ======= > +Package Core CPU Bzy_MHz > +======= ==== ==== ======= > +... > +0 12 12 3200 > +0 13 13 3200 > + > +======= ==== ==== ======= > diff --git a/Documentation/admin-guide/pm/working-state.rst b/Documentation/admin-guide/pm/working-state.rst > index fc298eb1234b..06d1403b1597 100644 > --- a/Documentation/admin-guide/pm/working-state.rst > +++ b/Documentation/admin-guide/pm/working-state.rst > @@ -11,3 +11,4 @@ Working-State Power Management > cpufreq > intel_pstate > intel_epb > + intel-speed-select > -- > 2.17.2 > -- With Best Regards, Andy Shevchenko
