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Groups > linux.kernel > #1701521
| Path | csiph.com!aioe.org!bofh.it!news.nic.it!robomod |
|---|---|
| From | Shivappa Vikas <vikas.shivappa@intel.com> |
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 16/28] x86/intel_rdt: Prepare to add RDT monitor cpus file support |
| Date | Tue, 01 Aug 2017 23:40:01 +0200 |
| Message-ID | <u9N3r-Rr-5@gated-at.bofh.it> (permalink) |
| References | <u7fpf-86t-3@gated-at.bofh.it> <u7fpi-86t-81@gated-at.bofh.it> <u9Ll0-8cw-31@gated-at.bofh.it> |
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| X-X-Sender | vikas@vshiva-Udesk |
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| Approved | robomod@news.nic.it |
| Lines | 40 |
| Organization | linux.* mail to news gateway |
| X-Original-Cc | Vikas Shivappa <vikas.shivappa@linux.intel.com>, vikas.shivappa@intel.com, x86@kernel.org, linux-kernel@vger.kernel.org, hpa@zytor.com, peterz@infradead.org, ravi.v.shankar@intel.com, tony.luck@intel.com, fenghua.yu@intel.com, eranian@google.com, davidcc@google.com, ak@linux.intel.com, reinette.chatre@intel.com |
| X-Original-Date | Tue, 1 Aug 2017 14:35:03 -0700 (PDT) |
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| X-Original-References | <1501017287-28083-1-git-send-email-vikas.shivappa@linux.intel.com> <1501017287-28083-17-git-send-email-vikas.shivappa@linux.intel.com> <alpine.DEB.2.20.1708012142530.2682@nanos> |
| X-Original-Sender | linux-kernel-owner@vger.kernel.org |
| Xref | csiph.com linux.kernel:1701521 |
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On Tue, 1 Aug 2017, Thomas Gleixner wrote:
> On Tue, 25 Jul 2017, Vikas Shivappa wrote:
>> /*
>> * The cached intel_pqr_state is strictly per CPU and can never be
>> * updated from a remote CPU. Functions which modify the state
>> @@ -49,6 +47,8 @@
>> */
>> DEFINE_PER_CPU(struct intel_pqr_state, pqr_state);
>>
>> +DEFINE_PER_CPU_READ_MOSTLY(struct intel_pqr_state, rdt_cpu_default);
>
> Cacheline wise this is suboptimal. You have to touch two cachelines on each
> context switch (at least for read).
>
> If you make that:
>
> struct intel_pqr_state {
> u32 default_cosid;
> u32 default_rmid;
> u32 cur_cosid;
> u32 cur_rmid;
> };
>
> DEFINE_PER_CPU(struct intel_pqr_state, pqr_state);
>
> then it's all together and you spare one cache line.
Will fix..
Thanks,
Vikas
>
> Thanks,
>
> tglx
>
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Re: [PATCH 16/28] x86/intel_rdt: Prepare to add RDT monitor cpus file support Thomas Gleixner <tglx@linutronix.de> - 2017-08-01 21:50 +0200 Re: [PATCH 16/28] x86/intel_rdt: Prepare to add RDT monitor cpus file support Shivappa Vikas <vikas.shivappa@intel.com> - 2017-08-01 23:40 +0200
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