.../admin-guide/kernel-parameters.txt | 26 ++- Documentation/admin-guide/pm/amd-pstate.rst | 11 + drivers/cpufreq/amd-pstate.c | 202 +++++++++++++++++- 3 files changed, 217 insertions(+), 22 deletions(-)
From ACPI spec[1] below 3 modes for CPPC can be defined:
1. Non autonomous: OS scaling governor specifies operating frequency/
performance level through `Desired Performance` register and PMFW
follows that.
2. Guided autonomous: OS scaling governor specifies min and max
frequencies/ performance levels through `Minimum Performance` and
`Maximum Performance` register, and PMFW can autonomously select an
operating frequency in this range.
3. Fully autonomous: OS only hints (via EPP) to PMFW for the required
energy performance preference for the workload and PMFW autonomously
scales the frequency.
Currently (1) is supported by amd_pstate as passive mode, and (3) is
implemented by EPP support[2]. This change is to support (2).
In guided autonomous mode the min_perf is based on the input from the
scaling governor. For example, in case of schedutil this value depends
on the current utilization. And max_perf is set to max capacity.
To activate guided auto mode ``amd_pstate=guided`` command line
parameter has to be passed in the kernel.
Below are the results (normalized) of benchmarks with this patch:
System: Genoa 96C 192T
Kernel: v6.1-rc6 + patch
Scaling governor: schedutil
================ tbench ================
tbench result comparison: (higher the better)
Here results are throughput (MB/s)
Clients acpi-cpufreq amd_pst+passive amd_pst+guided
1 1.00 (0.00 pct) 1.16 (16.00 pct) 2.20 (120.00 pct)
2 1.97 (0.00 pct) 2.29 (16.24 pct) 4.38 (122.33 pct)
4 3.95 (0.00 pct) 4.51 (14.17 pct) 8.50 (115.18 pct)
8 7.83 (0.00 pct) 8.89 (13.53 pct) 16.62 (112.26 pct)
16 15.28 (0.00 pct) 16.81 (10.01 pct) 31.02 (103.01 pct)
32 41.64 (0.00 pct) 30.67 (-26.34 pct) 55.63 (33.59 pct)
64 91.29 (0.00 pct) 79.67 (-12.72 pct) 91.74 (0.49 pct)
128 118.06 (0.00 pct) 122.34 (3.62 pct) 122.04 (3.37 pct)
256 260.47 (0.00 pct) 264.31 (1.47 pct) 264.49 (1.54 pct)
512 254.16 (0.00 pct) 245.25 (-3.50 pct) 245.50 (-3.40 pct)
tbench power comparison: (lower the better)
Clients acpi-cpufreq amd_pst+passive amd_pst+guided
1 1.00 (0.00 pct) 1.00 (0.00 pct) 1.15 (15.00 pct)
2 0.99 (0.00 pct) 1.00 (1.01 pct) 1.17 (18.18 pct)
4 1.01 (0.00 pct) 1.02 (0.99 pct) 1.24 (22.77 pct)
8 1.05 (0.00 pct) 1.06 (0.95 pct) 1.36 (29.52 pct)
16 1.15 (0.00 pct) 1.13 (-1.73 pct) 1.58 (37.39 pct)
32 1.71 (0.00 pct) 1.30 (-23.97 pct) 1.96 (14.61 pct)
64 2.35 (0.00 pct) 2.15 (-8.51 pct) 2.36 (0.42 pct)
128 2.77 (0.00 pct) 2.77 (0.00 pct) 2.78 (0.36 pct)
256 3.39 (0.00 pct) 3.41 (0.58 pct) 3.43 (1.17 pct)
512 3.42 (0.00 pct) 3.40 (-0.58 pct) 3.41 (-0.29 pct)
================ dbench ================
dbench result comparison: (higher the better)
Here results are throughput (MB/s)
Clients acpi-cpufreq amd_pst+passive amd_pst+guided
1 1.00 (0.00 pct) 0.96 (-4.00 pct) 1.02 (2.00 pct)
2 1.89 (0.00 pct) 1.90 (0.52 pct) 1.91 (1.05 pct)
4 3.39 (0.00 pct) 3.31 (-2.35 pct) 3.38 (-0.29 pct)
8 5.56 (0.00 pct) 5.46 (-1.79 pct) 5.60 (0.71 pct)
16 7.25 (0.00 pct) 7.90 (8.96 pct) 8.29 (14.34 pct)
32 10.85 (0.00 pct) 10.00 (-7.83 pct) 10.40 (-4.14 pct)
64 12.30 (0.00 pct) 11.94 (-2.92 pct) 11.82 (-3.90 pct)
128 12.56 (0.00 pct) 12.30 (-2.07 pct) 12.98 (3.34 pct)
256 6.55 (0.00 pct) 6.54 (-0.15 pct) 7.38 (12.67 pct)
512 1.61 (0.00 pct) 1.58 (-1.86 pct) 1.95 (21.11 pct)
dbench power comparison: (lower the better)
Clients acpi-cpufreq amd_pst+passive amd_pst+guided
1 1.00 (0.00 pct) 1.01 (1.00 pct) 1.05 (5.00 pct)
2 1.07 (0.00 pct) 1.07 (0.00 pct) 1.09 (1.86 pct)
4 1.15 (0.00 pct) 1.15 (0.00 pct) 1.16 (0.86 pct)
8 1.26 (0.00 pct) 1.26 (0.00 pct) 1.27 (0.79 pct)
16 1.39 (0.00 pct) 1.41 (1.43 pct) 1.43 (2.87 pct)
32 1.60 (0.00 pct) 1.56 (-2.50 pct) 1.59 (-0.62 pct)
64 1.75 (0.00 pct) 1.75 (0.00 pct) 1.74 (-0.57 pct)
128 1.90 (0.00 pct) 1.91 (0.52 pct) 1.93 (1.57 pct)
256 1.76 (0.00 pct) 1.77 (0.56 pct) 1.85 (5.11 pct)
512 1.55 (0.00 pct) 1.49 (-3.87 pct) 1.73 (11.61 pct)
================ git-source ================
git-source result comparison: (higher the better)
Here results are throughput (compilations per 1000 sec)
Threads acpi-cpufreq amd_pst+passive amd_pst+guided
192 1000.00 (0.00 pct) 943.00 (-5.70 pct) 1000.00 (0.00 pct)
git-source power comparison: (lower the better)
Threads acpi-cpufreq amd_pst+passive amd_pst+guided
192 1.00 (0.00 pct) 1.03 (3.00 pct) 1.02 (2.00 pct)
================ kernbench ================
kernbench result comparison: (higher the better)
Here results are throughput (compilations per 1000 sec)
Load acpi-cpufreq amd_pst+passive amd_pst+guided
32 1.00 (0.00 pct) 0.94 (-6.00 pct) 1.02 (2.00 pct)
48 1.24 (0.00 pct) 1.16 (-6.45 pct) 1.24 (0.00 pct)
64 1.35 (0.00 pct) 1.30 (-3.70 pct) 1.39 (2.96 pct)
96 1.42 (0.00 pct) 1.28 (-9.85 pct) 1.48 (4.22 pct)
128 1.39 (0.00 pct) 1.29 (-7.19 pct) 1.41 (1.43 pct)
192 1.32 (0.00 pct) 1.18 (-10.60 pct) 1.32 (0.00 pct)
256 1.28 (0.00 pct) 1.14 (-10.93 pct) 1.29 (0.78 pct)
384 1.28 (0.00 pct) 1.13 (-11.71 pct) 1.27 (-0.78 pct)
git-source power comparison: (lower the better)
Clients acpi-cpufreq amd_pst+passive amd_pst+guided
32 1.00 (0.00 pct) 1.04 (4.00 pct) 0.95 (-5.00 pct)
48 0.83 (0.00 pct) 0.90 (8.43 pct) 0.82 (-1.20 pct)
64 0.80 (0.00 pct) 0.82 (2.50 pct) 0.75 (-6.25 pct)
96 0.77 (0.00 pct) 0.81 (5.19 pct) 0.75 (-2.59 pct)
128 0.78 (0.00 pct) 0.82 (5.12 pct) 0.75 (-3.84 pct)
192 0.84 (0.00 pct) 0.89 (5.95 pct) 0.83 (-1.19 pct)
256 0.84 (0.00 pct) 0.89 (5.95 pct) 0.84 (0.00 pct)
384 0.84 (0.00 pct) 0.90 (7.14 pct) 0.84 (0.00 pct)
[1]: https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
[2]: https://lore.kernel.org/lkml/20221110175847.3098728-1-Perry.Yuan@amd.com/
Wyes Karny (4):
cpufreq: amd_pstate: Add guided autonomous mode
Documentation: amd_pstate: Move amd_pstate param to alphabetical order
cpufreq: amd_pstate: Expose sysfs interface to control state
Documentation: amd_pstate: Add amd_pstate state sysfs file
.../admin-guide/kernel-parameters.txt | 26 ++-
Documentation/admin-guide/pm/amd-pstate.rst | 11 +
drivers/cpufreq/amd-pstate.c | 202 +++++++++++++++++-
3 files changed, 217 insertions(+), 22 deletions(-)
--
2.34.1
On Wed, Dec 7, 2022 at 4:47 PM Wyes Karny <wyes.karny@amd.com> wrote: > > From ACPI spec[1] below 3 modes for CPPC can be defined: > 1. Non autonomous: OS scaling governor specifies operating frequency/ > performance level through `Desired Performance` register and PMFW > follows that. > 2. Guided autonomous: OS scaling governor specifies min and max > frequencies/ performance levels through `Minimum Performance` and > `Maximum Performance` register, and PMFW can autonomously select an > operating frequency in this range. > 3. Fully autonomous: OS only hints (via EPP) to PMFW for the required > energy performance preference for the workload and PMFW autonomously > scales the frequency. > > Currently (1) is supported by amd_pstate as passive mode, and (3) is > implemented by EPP support[2]. This change is to support (2). Well, can you guys please agree on priorities? Like which one is more important and so it should go in first? At this point I'm not sure what the ordering assumptions with respect to the EPP series are. Also this submission is late for 6.2, so I will only regard it as 6.3 material on the condition the above gets clarified. In the meantime, please address review comments and consider resending after 6.2-rc1 is out. Thanks!
Hi Rafael, On 12/8/2022 5:18 PM, Rafael J. Wysocki wrote: > Well, can you guys please agree on priorities? Like which one is more > important and so it should go in first? > > At this point I'm not sure what the ordering assumptions with respect > to the EPP series are. I am working with Perry on this and we will post a new patchset. Meanwhile, any review comments on this patchset is welcome. > > Also this submission is late for 6.2, so I will only regard it as 6.3 > material on the condition the above gets clarified. In the meantime, > please address review comments and consider resending after 6.2-rc1 is > out. Sure, Thanks! -- Thanks & Regards, Wyes
© 2016 - 2025 Red Hat, Inc.