diff options
| author | Changbin Du <changbin.du@gmail.com> | 2019-04-24 13:53:03 -0400 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2019-04-25 17:07:20 -0400 |
| commit | 3e57460f007c86476c376a08e31da441cae0b195 (patch) | |
| tree | f798e311307d9ed3c856798cf53e17d2bba03462 | |
| parent | 440ebec745dcbc44866f6b19e5145a12d4494a5f (diff) | |
Documentation: ACPI: move cppc_sysfs.txt to admin-guide/acpi and convert to reST
This converts the plain text documentation to reStructuredText format
and adds it to Sphinx TOC tree.
No essential content change.
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
| -rw-r--r-- | Documentation/admin-guide/acpi/cppc_sysfs.rst (renamed from Documentation/acpi/cppc_sysfs.txt) | 71 | ||||
| -rw-r--r-- | Documentation/admin-guide/acpi/index.rst | 1 |
2 files changed, 40 insertions, 32 deletions
diff --git a/Documentation/acpi/cppc_sysfs.txt b/Documentation/admin-guide/acpi/cppc_sysfs.rst index f20fb445135d..a4b99afbe331 100644 --- a/Documentation/acpi/cppc_sysfs.txt +++ b/Documentation/admin-guide/acpi/cppc_sysfs.rst | |||
| @@ -1,5 +1,11 @@ | |||
| 1 | .. SPDX-License-Identifier: GPL-2.0 | ||
| 1 | 2 | ||
| 2 | Collaborative Processor Performance Control (CPPC) | 3 | ================================================== |
| 4 | Collaborative Processor Performance Control (CPPC) | ||
| 5 | ================================================== | ||
| 6 | |||
| 7 | CPPC | ||
| 8 | ==== | ||
| 3 | 9 | ||
| 4 | CPPC defined in the ACPI spec describes a mechanism for the OS to manage the | 10 | CPPC defined in the ACPI spec describes a mechanism for the OS to manage the |
| 5 | performance of a logical processor on a contigious and abstract performance | 11 | performance of a logical processor on a contigious and abstract performance |
| @@ -10,31 +16,28 @@ For more details on CPPC please refer to the ACPI specification at: | |||
| 10 | 16 | ||
| 11 | http://uefi.org/specifications | 17 | http://uefi.org/specifications |
| 12 | 18 | ||
| 13 | Some of the CPPC registers are exposed via sysfs under: | 19 | Some of the CPPC registers are exposed via sysfs under:: |
| 14 | |||
| 15 | /sys/devices/system/cpu/cpuX/acpi_cppc/ | ||
| 16 | |||
| 17 | for each cpu X | ||
| 18 | 20 | ||
| 19 | -------------------------------------------------------------------------------- | 21 | /sys/devices/system/cpu/cpuX/acpi_cppc/ |
| 20 | 22 | ||
| 21 | $ ls -lR /sys/devices/system/cpu/cpu0/acpi_cppc/ | 23 | for each cpu X:: |
| 22 | /sys/devices/system/cpu/cpu0/acpi_cppc/: | ||
| 23 | total 0 | ||
| 24 | -r--r--r-- 1 root root 65536 Mar 5 19:38 feedback_ctrs | ||
| 25 | -r--r--r-- 1 root root 65536 Mar 5 19:38 highest_perf | ||
| 26 | -r--r--r-- 1 root root 65536 Mar 5 19:38 lowest_freq | ||
| 27 | -r--r--r-- 1 root root 65536 Mar 5 19:38 lowest_nonlinear_perf | ||
| 28 | -r--r--r-- 1 root root 65536 Mar 5 19:38 lowest_perf | ||
| 29 | -r--r--r-- 1 root root 65536 Mar 5 19:38 nominal_freq | ||
| 30 | -r--r--r-- 1 root root 65536 Mar 5 19:38 nominal_perf | ||
| 31 | -r--r--r-- 1 root root 65536 Mar 5 19:38 reference_perf | ||
| 32 | -r--r--r-- 1 root root 65536 Mar 5 19:38 wraparound_time | ||
| 33 | 24 | ||
| 34 | -------------------------------------------------------------------------------- | 25 | $ ls -lR /sys/devices/system/cpu/cpu0/acpi_cppc/ |
| 26 | /sys/devices/system/cpu/cpu0/acpi_cppc/: | ||
| 27 | total 0 | ||
| 28 | -r--r--r-- 1 root root 65536 Mar 5 19:38 feedback_ctrs | ||
| 29 | -r--r--r-- 1 root root 65536 Mar 5 19:38 highest_perf | ||
| 30 | -r--r--r-- 1 root root 65536 Mar 5 19:38 lowest_freq | ||
| 31 | -r--r--r-- 1 root root 65536 Mar 5 19:38 lowest_nonlinear_perf | ||
| 32 | -r--r--r-- 1 root root 65536 Mar 5 19:38 lowest_perf | ||
| 33 | -r--r--r-- 1 root root 65536 Mar 5 19:38 nominal_freq | ||
| 34 | -r--r--r-- 1 root root 65536 Mar 5 19:38 nominal_perf | ||
| 35 | -r--r--r-- 1 root root 65536 Mar 5 19:38 reference_perf | ||
| 36 | -r--r--r-- 1 root root 65536 Mar 5 19:38 wraparound_time | ||
| 35 | 37 | ||
| 36 | * highest_perf : Highest performance of this processor (abstract scale). | 38 | * highest_perf : Highest performance of this processor (abstract scale). |
| 37 | * nominal_perf : Highest sustained performance of this processor (abstract scale). | 39 | * nominal_perf : Highest sustained performance of this processor |
| 40 | (abstract scale). | ||
| 38 | * lowest_nonlinear_perf : Lowest performance of this processor with nonlinear | 41 | * lowest_nonlinear_perf : Lowest performance of this processor with nonlinear |
| 39 | power savings (abstract scale). | 42 | power savings (abstract scale). |
| 40 | * lowest_perf : Lowest performance of this processor (abstract scale). | 43 | * lowest_perf : Lowest performance of this processor (abstract scale). |
| @@ -48,22 +51,26 @@ total 0 | |||
| 48 | * feedback_ctrs : Includes both Reference and delivered performance counter. | 51 | * feedback_ctrs : Includes both Reference and delivered performance counter. |
| 49 | Reference counter ticks up proportional to processor's reference performance. | 52 | Reference counter ticks up proportional to processor's reference performance. |
| 50 | Delivered counter ticks up proportional to processor's delivered performance. | 53 | Delivered counter ticks up proportional to processor's delivered performance. |
| 51 | * wraparound_time: Minimum time for the feedback counters to wraparound (seconds). | 54 | * wraparound_time: Minimum time for the feedback counters to wraparound |
| 55 | (seconds). | ||
| 52 | * reference_perf : Performance level at which reference performance counter | 56 | * reference_perf : Performance level at which reference performance counter |
| 53 | accumulates (abstract scale). | 57 | accumulates (abstract scale). |
| 54 | 58 | ||
| 55 | -------------------------------------------------------------------------------- | ||
| 56 | 59 | ||
| 57 | Computing Average Delivered Performance | 60 | Computing Average Delivered Performance |
| 61 | ======================================= | ||
| 62 | |||
| 63 | Below describes the steps to compute the average performance delivered by | ||
| 64 | taking two different snapshots of feedback counters at time T1 and T2. | ||
| 65 | |||
| 66 | T1: Read feedback_ctrs as fbc_t1 | ||
| 67 | Wait or run some workload | ||
| 58 | 68 | ||
| 59 | Below describes the steps to compute the average performance delivered by taking | 69 | T2: Read feedback_ctrs as fbc_t2 |
| 60 | two different snapshots of feedback counters at time T1 and T2. | ||
| 61 | 70 | ||
| 62 | T1: Read feedback_ctrs as fbc_t1 | 71 | :: |
| 63 | Wait or run some workload | ||
| 64 | T2: Read feedback_ctrs as fbc_t2 | ||
| 65 | 72 | ||
| 66 | delivered_counter_delta = fbc_t2[del] - fbc_t1[del] | 73 | delivered_counter_delta = fbc_t2[del] - fbc_t1[del] |
| 67 | reference_counter_delta = fbc_t2[ref] - fbc_t1[ref] | 74 | reference_counter_delta = fbc_t2[ref] - fbc_t1[ref] |
| 68 | 75 | ||
| 69 | delivered_perf = (refernce_perf x delivered_counter_delta) / reference_counter_delta | 76 | delivered_perf = (refernce_perf x delivered_counter_delta) / reference_counter_delta |
diff --git a/Documentation/admin-guide/acpi/index.rst b/Documentation/admin-guide/acpi/index.rst index d68e9914c5ff..9049a7b9f065 100644 --- a/Documentation/admin-guide/acpi/index.rst +++ b/Documentation/admin-guide/acpi/index.rst | |||
| @@ -10,3 +10,4 @@ the Linux ACPI support. | |||
| 10 | 10 | ||
| 11 | initrd_table_override | 11 | initrd_table_override |
| 12 | dsdt-override | 12 | dsdt-override |
| 13 | cppc_sysfs | ||
