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Message-ID: <e534dafea0a138777e46f41b8c33618148a79d57.camel@linux.intel.com>
Date: Tue, 09 Oct 2018 13:41:57 -0700
From: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>,
Len Brown <lenb@...nel.org>,
Robert Moore <robert.moore@...el.com>,
"Schmauss, Erik" <erik.schmauss@...el.com>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
devel@...ica.org, Linux PM <linux-pm@...r.kernel.org>,
Prashanth Prakash <pprakash@...eaurora.org>,
George Cherian <george.cherian@...ium.com>
Subject: Re: [RESEND][PATCH] ACPI / CPPC: Add support for guaranteed
performance
On Tue, 2018-10-09 at 09:35 +0200, Rafael J. Wysocki wrote:
> On Mon, Oct 8, 2018 at 6:55 PM Srinivas Pandruvada
> <srinivas.pandruvada@...ux.intel.com> wrote:
> >
> > The Continuous Performance Control Package can have guaranteed
> > performance
> > field. Add support to read guaranteed performance.
>
> The spec says that it is optional, but you seem to assume that it
> always will be there.
>
Even if there is some missing optional field, the place will not be
filled by the next mandatory field as the order of fields is _CPC is
fixed.
"Optional _CPC package fields that are not supported by the platform
should be encoded as follows:
• Integer fields: Integer 0
• Register fields: the following NULL register descriptor should be
used:
ResourceTemplate() {Register {(SystemMemory, 0, 0, 0, 0)}}
"
> What happens if it is not there?
Will see 0 acpi_cppc sysfs.
But this may confuse users, so better not to add guaranteed attribute
to acpi_cppc sysfs.
I will submit v2 of patch series.
Thanks,
Srinivas
>
> > Signed-off-by: Srinivas Pandruvada <
> > srinivas.pandruvada@...ux.intel.com>
> > ---
> > No changes. But adding CC to mailing lists.
> >
> > Documentation/acpi/cppc_sysfs.txt | 2 ++
> > drivers/acpi/cppc_acpi.c | 10 ++++++++--
> > include/acpi/cppc_acpi.h | 1 +
> > 3 files changed, 11 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/acpi/cppc_sysfs.txt
> > b/Documentation/acpi/cppc_sysfs.txt
> > index f20fb445135d..812574d30717 100644
> > --- a/Documentation/acpi/cppc_sysfs.txt
> > +++ b/Documentation/acpi/cppc_sysfs.txt
> > @@ -22,6 +22,7 @@ $ ls -lR /sys/devices/system/cpu/cpu0/acpi_cppc/
> > /sys/devices/system/cpu/cpu0/acpi_cppc/:
> > total 0
> > -r--r--r-- 1 root root 65536 Mar 5 19:38 feedback_ctrs
> > +-r--r--r-- 1 root root 65536 Mar 5 19:38 guaranteed_perf
> > -r--r--r-- 1 root root 65536 Mar 5 19:38 highest_perf
> > -r--r--r-- 1 root root 65536 Mar 5 19:38 lowest_freq
> > -r--r--r-- 1 root root 65536 Mar 5 19:38 lowest_nonlinear_perf
> > @@ -33,6 +34,7 @@ total 0
> >
> > ----------------------------------------------------------------
> > ----------------
> >
> > +* guaranteed_perf : Guaranteed performance of this processor
> > (abstract scale).
> > * highest_perf : Highest performance of this processor (abstract
> > scale).
> > * nominal_perf : Highest sustained performance of this processor
> > (abstract scale).
> > * lowest_nonlinear_perf : Lowest performance of this processor
> > with nonlinear
> > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> > index d9ce4b162e2c..5babb9402f11 100644
> > --- a/drivers/acpi/cppc_acpi.c
> > +++ b/drivers/acpi/cppc_acpi.c
> > @@ -153,6 +153,7 @@ __ATTR(_name, 0444, show_##_name, NULL)
> > }
> > \
> > define_one_cppc_ro(member_name)
> >
> > +show_cppc_data(cppc_get_perf_caps, cppc_perf_caps,
> > guaranteed_perf);
> > show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, highest_perf);
> > show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_perf);
> > show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_perf);
> > @@ -189,6 +190,7 @@ static struct attribute *cppc_attrs[] = {
> > &nominal_perf.attr,
> > &nominal_freq.attr,
> > &lowest_freq.attr,
> > + &guaranteed_perf.attr,
> > NULL
> > };
> >
> > @@ -1061,9 +1063,9 @@ int cppc_get_perf_caps(int cpunum, struct
> > cppc_perf_caps *perf_caps)
> > {
> > struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
> > struct cpc_register_resource *highest_reg, *lowest_reg,
> > - *lowest_non_linear_reg, *nominal_reg,
> > + *lowest_non_linear_reg, *nominal_reg,
> > *guaranteed_reg,
> > *low_freq_reg = NULL, *nom_freq_reg = NULL;
> > - u64 high, low, nom, min_nonlinear, low_f = 0, nom_f = 0;
> > + u64 high, low, guaranteed, nom, min_nonlinear, low_f = 0,
> > nom_f = 0;
> > int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
> > struct cppc_pcc_data *pcc_ss_data = NULL;
> > int ret = 0, regs_in_pcc = 0;
> > @@ -1079,6 +1081,7 @@ int cppc_get_perf_caps(int cpunum, struct
> > cppc_perf_caps *perf_caps)
> > nominal_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
> > low_freq_reg = &cpc_desc->cpc_regs[LOWEST_FREQ];
> > nom_freq_reg = &cpc_desc->cpc_regs[NOMINAL_FREQ];
> > + guaranteed_reg = &cpc_desc->cpc_regs[GUARANTEED_PERF];
> >
> > /* Are any of the regs PCC ?*/
> > if (CPC_IN_PCC(highest_reg) || CPC_IN_PCC(lowest_reg) ||
> > @@ -1107,6 +1110,9 @@ int cppc_get_perf_caps(int cpunum, struct
> > cppc_perf_caps *perf_caps)
> > cpc_read(cpunum, nominal_reg, &nom);
> > perf_caps->nominal_perf = nom;
> >
> > + cpc_read(cpunum, guaranteed_reg, &guaranteed);
> > + perf_caps->guaranteed_perf = guaranteed;
> > +
> > cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear);
> > perf_caps->lowest_nonlinear_perf = min_nonlinear;
> >
> > diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
> > index 8e0b8250a139..cf59e6210d27 100644
> > --- a/include/acpi/cppc_acpi.h
> > +++ b/include/acpi/cppc_acpi.h
> > @@ -104,6 +104,7 @@ enum cppc_regs {
> > * today.
> > */
> > struct cppc_perf_caps {
> > + u32 guaranteed_perf;
> > u32 highest_perf;
> > u32 nominal_perf;
> > u32 lowest_perf;
> > --
> > 2.17.1
> >
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