Messages in this thread | | | Date | Tue, 21 Sep 2021 20:50:13 -0700 | Subject | Re: [PATCH] x86/ACPI/State: Optimize C3 entry on AMD CPUs | From | "Sharma, Deepak" <> |
| |
Hi Rafael,
On 9/1/2021 5:45 AM, Rafael J. Wysocki wrote: > On Wed, Sep 1, 2021 at 4:14 AM Deepak Sharma <deesharm@amd.com> wrote: >> >> On 8/25/21 11:07 AM, Rafael J. Wysocki wrote: >>> On Thu, Aug 19, 2021 at 2:43 AM Deepak Sharma <deepak.sharma@amd.com> wrote: >>>> AMD CPU which support C3 shares cache. Its not necessary to flush the >>>> caches in software before entering C3. This will cause performance drop >>>> for the cores which share some caches. ARB_DIS is not used with current >>>> AMD C state implementation. So set related flags correctly. >>>> >>>> Signed-off-by: Deepak Sharma <deepak.sharma@amd.com> >>> Applied as 5.15 material under the edited subject "x86: ACPI: cstate: >>> Optimize C3 entry on AMD CPUs", thanks! >> I might need to send subsequent patch for this. Can you please point me >> to git and branch where this has been merged. > git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
Still I am not able to see this patch merged on linux-next branch.
Thanks,
Deepak
>>>> --- >>>> arch/x86/kernel/acpi/cstate.c | 15 +++++++++++++++ >>>> 1 file changed, 15 insertions(+) >>>> >>>> diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c >>>> index 7de599eba7f0..62a5986d625a 100644 >>>> --- a/arch/x86/kernel/acpi/cstate.c >>>> +++ b/arch/x86/kernel/acpi/cstate.c >>>> @@ -79,6 +79,21 @@ void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags, >>>> */ >>>> flags->bm_control = 0; >>>> } >>>> + if (c->x86_vendor == X86_VENDOR_AMD) { >>>> + /* >>>> + * For all AMD CPUs that support C3, caches should not be >>>> + * flushed by software while entering C3 type state. Set >>>> + * bm->check to 1 so that kernel doesn't need to execute >>>> + * cache flush operation. >>>> + */ >>>> + flags->bm_check = 1; >>>> + /* >>>> + * In current AMD C state implementation ARB_DIS is no longer >>>> + * used. So set bm_control to zero to indicate ARB_DIS is not >>>> + * required while entering C3 type state. >>>> + */ >>>> + flags->bm_control = 0; >>>> + } >>>> } >>>> EXPORT_SYMBOL(acpi_processor_power_init_bm_check); >>>> >>>> -- >>>> 2.25.1 >>>>
| |