<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/drivers/cpufreq/intel_pstate.c, branch v6.9</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge back cpufreq material for 6.9-rc1.</title>
<updated>2024-03-11T14:08:45+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2024-03-11T14:08:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e4d0d7f194b929ca0af048bdedb71266c2e75191'/>
<id>e4d0d7f194b929ca0af048bdedb71266c2e75191</id>
<content type='text'>
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: intel_pstate: Update default EPPs for Meteor Lake</title>
<updated>2024-02-24T14:02:33+00:00</updated>
<author>
<name>Srinivas Pandruvada</name>
<email>srinivas.pandruvada@linux.intel.com</email>
</author>
<published>2024-02-20T02:26:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1f4b7fdd71e066aa7c01e3e26ceeb39b47dd5461'/>
<id>1f4b7fdd71e066aa7c01e3e26ceeb39b47dd5461</id>
<content type='text'>
Update default balanced_performance EPP to 115 and performance EPP to 16.

Changing the balanced_performance EPP has better performance/watt
compared to default powerup EPP value of 128.

Changing the performance EPP to 0x10 shows reduced power for similar
performance as EPP 0. On small form factor devices this is beneficial
as lower power results in lower CPU and skin temperature. This
results in reduced thermal throttling and higher performance.

Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Update default balanced_performance EPP to 115 and performance EPP to 16.

Changing the balanced_performance EPP has better performance/watt
compared to default powerup EPP value of 128.

Changing the performance EPP to 0x10 shows reduced power for similar
performance as EPP 0. On small form factor devices this is beneficial
as lower power results in lower CPU and skin temperature. This
results in reduced thermal throttling and higher performance.

Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: intel_pstate: Allow model specific EPPs</title>
<updated>2024-02-24T14:02:33+00:00</updated>
<author>
<name>Srinivas Pandruvada</name>
<email>srinivas.pandruvada@linux.intel.com</email>
</author>
<published>2024-02-20T02:26:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=240a8da623008eb9f4e32c7a19ce16a6605911dc'/>
<id>240a8da623008eb9f4e32c7a19ce16a6605911dc</id>
<content type='text'>
The current implementation allows model specific EPP override for
balanced_performance. Add feature to allow model specific EPP for all
predefined EPP strings. For example for some CPU models, even changing
performance EPP has benefits

Use a mask of EPPs as driver_data instead of just balanced_performance.

Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The current implementation allows model specific EPP override for
balanced_performance. Add feature to allow model specific EPP for all
predefined EPP strings. For example for some CPU models, even changing
performance EPP has benefits

Use a mask of EPPs as driver_data instead of just balanced_performance.

Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: intel_pstate: fix pstate limits enforcement for adjust_perf call back</title>
<updated>2024-02-24T14:01:59+00:00</updated>
<author>
<name>Doug Smythies</name>
<email>dsmythies@telus.net</email>
</author>
<published>2024-02-17T21:30:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f0a0fc10abb062d122db5ac4ed42f6d1ca342649'/>
<id>f0a0fc10abb062d122db5ac4ed42f6d1ca342649</id>
<content type='text'>
There is a loophole in pstate limit clamping for the intel_cpufreq CPU
frequency scaling driver (intel_pstate in passive mode), schedutil CPU
frequency scaling governor, HWP (HardWare Pstate) control enabled, when
the adjust_perf call back path is used.

Fix it.

Fixes: a365ab6b9dfb cpufreq: intel_pstate: Implement the -&gt;adjust_perf() callback
Signed-off-by: Doug Smythies &lt;dsmythies@telus.net&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There is a loophole in pstate limit clamping for the intel_cpufreq CPU
frequency scaling driver (intel_pstate in passive mode), schedutil CPU
frequency scaling governor, HWP (HardWare Pstate) control enabled, when
the adjust_perf call back path is used.

Fix it.

Fixes: a365ab6b9dfb cpufreq: intel_pstate: Implement the -&gt;adjust_perf() callback
Signed-off-by: Doug Smythies &lt;dsmythies@telus.net&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: intel_pstate: remove cpudata::prev_cummulative_iowait</title>
<updated>2024-02-13T12:47:35+00:00</updated>
<author>
<name>Jiri Slaby (SUSE)</name>
<email>jirislaby@kernel.org</email>
</author>
<published>2024-02-13T11:16:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=4615ac9010be84d676f9e893e5a7ea4b5febd1e8'/>
<id>4615ac9010be84d676f9e893e5a7ea4b5febd1e8</id>
<content type='text'>
Commit 09c448d3c61f ("cpufreq: intel_pstate: Use IOWAIT flag in Atom
algorithm") removed the last user of cpudata::prev_cummulative_iowait.
Remove the member too.

Found by https://github.com/jirislaby/clang-struct.

Signed-off-by: Jiri Slaby (SUSE) &lt;jirislaby@kernel.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 09c448d3c61f ("cpufreq: intel_pstate: Use IOWAIT flag in Atom
algorithm") removed the last user of cpudata::prev_cummulative_iowait.
Remove the member too.

Found by https://github.com/jirislaby/clang-struct.

Signed-off-by: Jiri Slaby (SUSE) &lt;jirislaby@kernel.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: intel_pstate: Refine computation of P-state for given frequency</title>
<updated>2024-01-22T14:18:11+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2024-01-22T14:18:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=192cdb1c907fd8df2d764c5bb17496e415e59391'/>
<id>192cdb1c907fd8df2d764c5bb17496e415e59391</id>
<content type='text'>
On systems using HWP, if a given frequency is equal to the maximum turbo
frequency or the maximum non-turbo frequency, the HWP performance level
corresponding to it is already known and can be used directly without
any computation.

Accordingly, adjust the code to use the known HWP performance levels in
the cases mentioned above.

This also helps to avoid limiting CPU capacity artificially in some
cases when the BIOS produces the HWP_CAP numbers using a different
E-core-to-P-core performance scaling factor than expected by the kernel.

Fixes: f5c8cf2a4992 ("cpufreq: intel_pstate: hybrid: Use known scaling factor for P-cores")
Cc: 6.1+ &lt;stable@vger.kernel.org&gt; # 6.1+
Tested-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
On systems using HWP, if a given frequency is equal to the maximum turbo
frequency or the maximum non-turbo frequency, the HWP performance level
corresponding to it is already known and can be used directly without
any computation.

Accordingly, adjust the code to use the known HWP performance levels in
the cases mentioned above.

This also helps to avoid limiting CPU capacity artificially in some
cases when the BIOS produces the HWP_CAP numbers using a different
E-core-to-P-core performance scaling factor than expected by the kernel.

Fixes: f5c8cf2a4992 ("cpufreq: intel_pstate: hybrid: Use known scaling factor for P-cores")
Cc: 6.1+ &lt;stable@vger.kernel.org&gt; # 6.1+
Tested-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: intel_pstate: Update hybrid scaling factor for Meteor Lake</title>
<updated>2024-01-10T14:02:25+00:00</updated>
<author>
<name>Srinivas Pandruvada</name>
<email>srinivas.pandruvada@linux.intel.com</email>
</author>
<published>2024-01-09T17:48:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=bde4f5ff8295601554601f78a523d4d97e42433e'/>
<id>bde4f5ff8295601554601f78a523d4d97e42433e</id>
<content type='text'>
On some Meteor Lake platforms, maximum one core turbo frequency is not
observed. During hybrid performance to frequency conversion, the maximum
frequency is 100 MHz less. This results in requesting maximum frequency
100 MHz less.

For example when the max one core turbo is 4.9 GHz:
MSR HWP_CAPABILITIES shows highest performance ratio for P-core is 0x3E.
With the current scaling factor of 78741 (1.27x for converting frequency
to performance) results in max frequency of 4.8 GHz. This results in
capping the max scaling frequency as 4.8 GHz, which is 100 MHz less than
the desired.

Add capability to define per CPU model specific scaling factor and define
scaling factor of 80000 (1.25x for converting frequency to performance for
P-cores) for Meteor Lake.

Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
[ rjw: Debug message adjustment, subject edit ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
On some Meteor Lake platforms, maximum one core turbo frequency is not
observed. During hybrid performance to frequency conversion, the maximum
frequency is 100 MHz less. This results in requesting maximum frequency
100 MHz less.

For example when the max one core turbo is 4.9 GHz:
MSR HWP_CAPABILITIES shows highest performance ratio for P-core is 0x3E.
With the current scaling factor of 78741 (1.27x for converting frequency
to performance) results in max frequency of 4.8 GHz. This results in
capping the max scaling frequency as 4.8 GHz, which is 100 MHz less than
the desired.

Add capability to define per CPU model specific scaling factor and define
scaling factor of 80000 (1.25x for converting frequency to performance for
P-cores) for Meteor Lake.

Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
[ rjw: Debug message adjustment, subject edit ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: intel_pstate: Add Emerald Rapids support in no-HWP mode</title>
<updated>2023-12-19T20:38:09+00:00</updated>
<author>
<name>Zhenguo Yao</name>
<email>yaozhenguo1@gmail.com</email>
</author>
<published>2023-12-13T10:28:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e95013156ad88e6a1e1db6545881f49183e2ee0a'/>
<id>e95013156ad88e6a1e1db6545881f49183e2ee0a</id>
<content type='text'>
Users may disable HWP in firmware, in which case intel_pstate will give up
unless the CPU model is explicitly supported.

See also the following past commits:

 - commit df51f287b5de ("cpufreq: intel_pstate: Add Sapphire Rapids support
   in no-HWP mode")
 - commit d8de7a44e11f ("cpufreq: intel_pstate: Add Skylake servers support")
 - commit 706c5328851d ("cpufreq: intel_pstate: Add Cometlake support in
   no-HWP mode")
 - commit fbdc21e9b038 ("cpufreq: intel_pstate: Add Icelake servers support in
   no-HWP mode")
 - commit 71bb5c82aaae ("cpufreq: intel_pstate: Add Tigerlake support in
   no-HWP mode")

Signed-off-by: Zhenguo Yao &lt;yaozhenguo1@gmail.com&gt;
Acked-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Users may disable HWP in firmware, in which case intel_pstate will give up
unless the CPU model is explicitly supported.

See also the following past commits:

 - commit df51f287b5de ("cpufreq: intel_pstate: Add Sapphire Rapids support
   in no-HWP mode")
 - commit d8de7a44e11f ("cpufreq: intel_pstate: Add Skylake servers support")
 - commit 706c5328851d ("cpufreq: intel_pstate: Add Cometlake support in
   no-HWP mode")
 - commit fbdc21e9b038 ("cpufreq: intel_pstate: Add Icelake servers support in
   no-HWP mode")
 - commit 71bb5c82aaae ("cpufreq: intel_pstate: Add Tigerlake support in
   no-HWP mode")

Signed-off-by: Zhenguo Yao &lt;yaozhenguo1@gmail.com&gt;
Acked-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: intel_pstate: Prioritize firmware-provided balance performance EPP</title>
<updated>2023-12-05T20:29:47+00:00</updated>
<author>
<name>Srinivas Pandruvada</name>
<email>srinivas.pandruvada@linux.intel.com</email>
</author>
<published>2023-11-20T18:59:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=2719675fa8111a8d7a060133e1dd4797d20c9754'/>
<id>2719675fa8111a8d7a060133e1dd4797d20c9754</id>
<content type='text'>
The platform firmware can provide a balance performance EPP value by
enabling HWP and programming the EPP to the desired value.

However, currently this only takes effect for processors listed in
intel_epp_balance_perf[], so in order to enable a new processor model
to utilize this mechanism, that table needs to be updated.  It arguably
should not be necessary to modify the kernel to work properly with
every new generation of processors, though, and distributions that don't
always ship the most recent kernels should be able to run reasonably well
on new hardware without code changes.

For this reason, move the check to avoid updating the EPP when the balance
performance EPP is unmodified from the power-up default of 0x80 after the
check that allows the firmware-provided balance performance EPP value to
be retrieved.  This will cause the code to always look for the firmware-
provided value before consulting intel_epp_balance_perf[] and the handling
of new hardware will not depend on whether or not that thable has been
updated yet.

Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The platform firmware can provide a balance performance EPP value by
enabling HWP and programming the EPP to the desired value.

However, currently this only takes effect for processors listed in
intel_epp_balance_perf[], so in order to enable a new processor model
to utilize this mechanism, that table needs to be updated.  It arguably
should not be necessary to modify the kernel to work properly with
every new generation of processors, though, and distributions that don't
always ship the most recent kernels should be able to run reasonably well
on new hardware without code changes.

For this reason, move the check to avoid updating the EPP when the balance
performance EPP is unmodified from the power-up default of 0x80 after the
check that allows the firmware-provided balance performance EPP value to
be retrieved.  This will cause the code to always look for the firmware-
provided value before consulting intel_epp_balance_perf[] and the handling
of new hardware will not depend on whether or not that thable has been
updated yet.

Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: intel_pstate: Revise global turbo disable check</title>
<updated>2023-09-11T18:18:17+00:00</updated>
<author>
<name>Srinivas Pandruvada</name>
<email>srinivas.pandruvada@linux.intel.com</email>
</author>
<published>2023-09-07T18:02:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=37b6ddba967c601479bea418a7ac6ff16b6232b7'/>
<id>37b6ddba967c601479bea418a7ac6ff16b6232b7</id>
<content type='text'>
Setting global turbo flag based on CPU 0 P-state limits is problematic
as it limits max P-state request on every CPU on the system just based
on its P-state limits.

There are two cases in which global.turbo_disabled flag is set:
- When the MSR_IA32_MISC_ENABLE_TURBO_DISABLE bit is set to 1
in the MSR MSR_IA32_MISC_ENABLE. This bit can be only changed by
the system BIOS before power up.
- When the max non turbo P-state is same as max turbo P-state for CPU 0.

The second check is not a valid to decide global turbo state based on
the CPU 0. CPU 0 max turbo P-state can be same as max non turbo P-state,
but for other CPUs this may not be true.

There is no guarantee that max P-state limits are same for every CPU. This
is possible that during fusing max P-state for a CPU is constrained. Also
with the Intel Speed Select performance profile, CPU 0 may not be present
in all profiles. In this case the max non turbo and turbo P-state can be
set to the lowest possible P-state by the hardware when switched to
such profile. Since max non turbo and turbo P-state is same,
global.turbo_disabled flag will be set.

Once global.turbo_disabled is set, any scaling max and min frequency
update for any CPU will result in its max P-state constrained to the max
non turbo P-state.

Hence remove the check of max non turbo P-state equal to max turbo P-state
of CPU 0 to set global turbo disabled flag.

Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
[ rjw: Subject edit ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Setting global turbo flag based on CPU 0 P-state limits is problematic
as it limits max P-state request on every CPU on the system just based
on its P-state limits.

There are two cases in which global.turbo_disabled flag is set:
- When the MSR_IA32_MISC_ENABLE_TURBO_DISABLE bit is set to 1
in the MSR MSR_IA32_MISC_ENABLE. This bit can be only changed by
the system BIOS before power up.
- When the max non turbo P-state is same as max turbo P-state for CPU 0.

The second check is not a valid to decide global turbo state based on
the CPU 0. CPU 0 max turbo P-state can be same as max non turbo P-state,
but for other CPUs this may not be true.

There is no guarantee that max P-state limits are same for every CPU. This
is possible that during fusing max P-state for a CPU is constrained. Also
with the Intel Speed Select performance profile, CPU 0 may not be present
in all profiles. In this case the max non turbo and turbo P-state can be
set to the lowest possible P-state by the hardware when switched to
such profile. Since max non turbo and turbo P-state is same,
global.turbo_disabled flag will be set.

Once global.turbo_disabled is set, any scaling max and min frequency
update for any CPU will result in its max P-state constrained to the max
non turbo P-state.

Hence remove the check of max non turbo P-state equal to max turbo P-state
of CPU 0 to set global turbo disabled flag.

Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
[ rjw: Subject edit ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
