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From: Tim Chen <tim.c.chen@linux.intel.com>
To: "Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com>,
	Peter Zijlstra <peterz@infradead.org>
Cc: "catalin.marinas@arm.com" <catalin.marinas@arm.com>,
	"will@kernel.org" <will@kernel.org>,
	"rjw@rjwysocki.net" <rjw@rjwysocki.net>,
	"vincent.guittot@linaro.org" <vincent.guittot@linaro.org>,
	"bp@alien8.de" <bp@alien8.de>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"lenb@kernel.org" <lenb@kernel.org>,
	"dietmar.eggemann@arm.com" <dietmar.eggemann@arm.com>,
	"rostedt@goodmis.org" <rostedt@goodmis.org>,
	"bsegall@google.com" <bsegall@google.com>,
	"mgorman@suse.de" <mgorman@suse.de>,
	"msys.mizuma@gmail.com" <msys.mizuma@gmail.com>,
	"valentin.schneider@arm.com" <valentin.schneider@arm.com>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	Jonathan Cameron <jonathan.cameron@huawei.com>,
	"juri.lelli@redhat.com" <juri.lelli@redhat.com>,
	"mark.rutland@arm.com" <mark.rutland@arm.com>,
	"sudeep.holla@arm.com" <sudeep.holla@arm.com>,
	"aubrey.li@linux.intel.com" <aubrey.li@linux.intel.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>,
	"xuwei (O)" <xuwei5@huawei.com>,
	"Zengtao (B)" <prime.zeng@hisilicon.com>,
	"guodong.xu@linaro.org" <guodong.xu@linaro.org>,
	yangyicong <yangyicong@huawei.com>,
	"Liguozhu (Kenneth)" <liguozhu@hisilicon.com>,
	"linuxarm@openeuler.org" <linuxarm@openeuler.org>,
	"hpa@zytor.com" <hpa@zytor.com>
Subject: Re: [Linuxarm] Re: [RFC PATCH v4 3/3] scheduler: Add cluster scheduler level for x86
Date: Mon, 15 Mar 2021 13:53:38 -0700	[thread overview]
Message-ID: <e23d04d3-723e-5733-a43a-601f58ecfee4@linux.intel.com> (raw)
In-Reply-To: <6d8940e227324c2c88474d9d0769c001@hisilicon.com>


> It seems sensible the more CPU we get in the cluster, the more
> we need the kernel to be aware of its existence.
> 
> Tim, it is possible for you to bring up the cpu_cluster_mask and
> cluster_sibling for x86 so that the topology can be represented
> in sysfs and be used by scheduler? It seems your patch lacks this
> part.

You mean having something in /sys/devices/system/cpu/cpu0/topology
on cluster information so that an external program can 
affinitize to a cluster if it prefers to do so?

Tim  

> 
> BTW, I wonder if x86 can do some improvement on your KMP_AFFINITY
> by leveraging the cluster topology level.
> https://software.intel.com/content/www/us/en/develop/documentation/cpp-compiler-developer-guide-and-reference/top/optimization-and-programming-guide/openmp-support/openmp-library-support/thread-affinity-interface-linux-and-windows.html
> 
> KMP_AFFINITY has thread affinity modes like compact and scatter,
> it seems this "compact" and "scatter" can also use the cluster
> information as you see we are also struggling with the "compact"
> and "scatter" issues here in this patchset :-)
> 
> Thanks
> Barry
> 

      reply	other threads:[~2021-03-15 20:54 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-01 22:59 [RFC PATCH v4 0/3] scheduler: expose the topology of clusters and add cluster scheduler Barry Song
2021-03-01 22:59 ` [RFC PATCH v4 1/3] topology: Represent clusters of CPUs within a die Barry Song
2021-03-15  3:11   ` Song Bao Hua (Barry Song)
2021-03-15 10:52     ` Jonathan Cameron
2021-03-01 22:59 ` [RFC PATCH v4 2/3] scheduler: add scheduler level for clusters Barry Song
2021-03-02 10:43   ` Peter Zijlstra
2021-03-16  7:33     ` Song Bao Hua (Barry Song)
2021-03-08 11:25   ` Vincent Guittot
2021-03-08 22:15     ` Song Bao Hua (Barry Song)
2021-03-01 22:59 ` [RFC PATCH v4 3/3] scheduler: Add cluster scheduler level for x86 Barry Song
2021-03-02 10:30   ` Peter Zijlstra
2021-03-03 18:34     ` Tim Chen
2021-03-08 22:30       ` [Linuxarm] " Song Bao Hua (Barry Song)
2021-03-15 20:53         ` Tim Chen [this message]

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