RE: [PATCH v1] power: support amd-pstate cpufreq driver

["Tummala, Sivaprasad" <Sivaprasad.Tummala@amd.com>]

[AMD Official Use Only - General]

Hi Thomas,

> -----Original Message-----
> From: Thomas Monjalon <thomas@monjalon.net>
> Sent: Thursday, May 25, 2023 12:17 AM
> To: Tummala, Sivaprasad <Sivaprasad.Tummala@amd.com>
> Cc: david.hunt@intel.com; dev@dpdk.org; Yigit, Ferruh <Ferruh.Yigit@amd.com>;
> anatoly.burakov@intel.com; Laatz, Kevin <kevin.laatz@intel.com>
> Subject: Re: [PATCH v1] power: support amd-pstate cpufreq driver
>
> Caution: This message originated from an External Source. Use proper caution
> when opening attachments, clicking links, or responding.
>
>
> 12/04/2023 11:52, Sivaprasad Tummala:
> > amd-pstate introduces a new CPU frequency control mechanism for AMD
> > processors using the ACPI Collaborative Performance Power Control
> > feature for a finer grained frequency management.
> >
> > Patch to add support for amd-pstate driver.
> >
> > Signed-off-by: Sivaprasad Tummala <Sivaprasad.Tummala@amd.com>
> > ---
> >  app/test/test_power.c                  |   1 +
> >  app/test/test_power_cpufreq.c          |   5 +-
> >  doc/guides/rel_notes/release_23_07.rst |   3 +
> >  examples/l3fwd-power/main.c            |   1 +
> >  lib/power/meson.build                  |   1 +
> >  lib/power/power_amd_pstate_cpufreq.c   | 698
> +++++++++++++++++++++++++
> >  lib/power/power_amd_pstate_cpufreq.h   | 219 ++++++++
> >  lib/power/rte_power.c                  |  26 +
> >  lib/power/rte_power.h                  |   3 +-
> >  lib/power/rte_power_pmd_mgmt.c         |   6 +-
> >  10 files changed, 958 insertions(+), 5 deletions(-)
>
> I'm not comfortable to merge this patch without a word from David Hunt.
> Given there is 0 review, what do we do?
Yes, we are waiting for feedback from the community on this patch.
>
>
> >       Also, make sure to start the actual text at the margin.
> >
> ====================================================
> ===
> >
> > +   * **Added amd-pstate driver support to power management library.**
> > +
> > +        Added support for amd-pstate driver which works on AMD Zen processors.
>
> Looks like the indent is not correct.
Sure, will fix it in v2 patch
>
> >          'power_pstate_cpufreq.c',
> > +        'power_amd_pstate_cpufreq.c',
>
> Can you say briefly why AMD has a different pstate?
> Does it mean power_pstate_cpufreq.c should be renamed
> power_intel_pstate_cpufreq.c?
amd-pstate is the new AMD CPU performance scaling driver based on CPPC.
It is implemented as a new kernel driver and we need a different library from
Power_pstate_cpufreq. Yes, it makes sense to rename this, inline with the
Linux kernel as indicated below.
linux/latest/source/drivers/cpufreq
 -  amd-pstate.c
 -   cppc_cpufreq.c
 -   intel_pstate.c
>
> > +++ b/lib/power/power_amd_pstate_cpufreq.c
> > @@ -0,0 +1,698 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause
> > + * Copyright(c) 2010-2021 Intel Corporation
> > + * Copyright(c) 2021 Arm Limited
>
> Why is there copyright for Intel and Arm?
> Does it mean you copied some code and did not try to keep common code in a
> common place?
Yes, few internal functions follow similar notion as power_cppc_cpufreq.c
>
> > + * Copyright(c) 2023 Amd Limited
>
>

Thanks & Regards,
Sivaprasad