From: Jonathan Cameron <Jonathan.Cameron@Huawei.com> To: "Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com> Cc: Greg KH <gregkh@linuxfoundation.org>, "tim.c.chen@linux.intel.com" <tim.c.chen@linux.intel.com>, "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>, "peterz@infradead.org" <peterz@infradead.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>, "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: [RFC PATCH v5 1/4] topology: Represent clusters of CPUs within a die Date: Fri, 19 Mar 2021 09:36:16 +0000 [thread overview] Message-ID: <20210319093616.00001879@Huawei.com> (raw) In-Reply-To: <eb48302277f3436eb9899032e6b0bf1c@hisilicon.com> On Fri, 19 Mar 2021 06:57:08 +0000 "Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com> wrote: > > -----Original Message----- > > From: Greg KH [mailto:gregkh@linuxfoundation.org] > > Sent: Friday, March 19, 2021 7:35 PM > > To: Song Bao Hua (Barry Song) <song.bao.hua@hisilicon.com> > > Cc: tim.c.chen@linux.intel.com; catalin.marinas@arm.com; will@kernel.org; > > rjw@rjwysocki.net; vincent.guittot@linaro.org; bp@alien8.de; > > tglx@linutronix.de; mingo@redhat.com; lenb@kernel.org; peterz@infradead.org; > > dietmar.eggemann@arm.com; rostedt@goodmis.org; bsegall@google.com; > > mgorman@suse.de; msys.mizuma@gmail.com; valentin.schneider@arm.com; Jonathan > > Cameron <jonathan.cameron@huawei.com>; juri.lelli@redhat.com; > > mark.rutland@arm.com; sudeep.holla@arm.com; aubrey.li@linux.intel.com; > > linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; > > linux-acpi@vger.kernel.org; x86@kernel.org; xuwei (O) <xuwei5@huawei.com>; > > Zengtao (B) <prime.zeng@hisilicon.com>; guodong.xu@linaro.org; yangyicong > > <yangyicong@huawei.com>; Liguozhu (Kenneth) <liguozhu@hisilicon.com>; > > linuxarm@openeuler.org; hpa@zytor.com > > Subject: Re: [RFC PATCH v5 1/4] topology: Represent clusters of CPUs within > > a die > > > > On Fri, Mar 19, 2021 at 05:16:15PM +1300, Barry Song wrote: > > > diff --git a/Documentation/admin-guide/cputopology.rst > > b/Documentation/admin-guide/cputopology.rst > > > index b90dafc..f9d3745 100644 > > > --- a/Documentation/admin-guide/cputopology.rst > > > +++ b/Documentation/admin-guide/cputopology.rst > > > @@ -24,6 +24,12 @@ core_id: > > > identifier (rather than the kernel's). The actual value is > > > architecture and platform dependent. > > > > > > +cluster_id: > > > + > > > + the Cluster ID of cpuX. Typically it is the hardware platform's > > > + identifier (rather than the kernel's). The actual value is > > > + architecture and platform dependent. > > > + > > > book_id: > > > > > > the book ID of cpuX. Typically it is the hardware platform's > > > @@ -56,6 +62,14 @@ package_cpus_list: > > > human-readable list of CPUs sharing the same physical_package_id. > > > (deprecated name: "core_siblings_list") > > > > > > +cluster_cpus: > > > + > > > + internal kernel map of CPUs within the same cluster. > > > + > > > +cluster_cpus_list: > > > + > > > + human-readable list of CPUs within the same cluster. > > > + > > > die_cpus: > > > > > > internal kernel map of CPUs within the same die. > > > > Why are these sysfs files in this file, and not in a Documentation/ABI/ > > file which can be correctly parsed and shown to userspace? > > Well. Those ABIs have been there for much a long time. It is like: > > [root@ceph1 topology]# ls > core_id core_siblings core_siblings_list physical_package_id thread_siblings thread_siblings_list > [root@ceph1 topology]# pwd > /sys/devices/system/cpu/cpu100/topology > [root@ceph1 topology]# cat core_siblings_list > 64-127 > [root@ceph1 topology]# > > > > > Any chance you can fix that up here as well? > > Yes. we will send a separate patch to address this, which won't > be in this patchset. This patchset will base on that one. > > > > > Also note that "list" is not something that goes in sysfs, sysfs is "one > > value per file", and a list is not "one value". How do you prevent > > overflowing the buffer of the sysfs file if you have a "list"? > > > > At a glance, the list is using "-" rather than a real list > [root@ceph1 topology]# cat core_siblings_list > 64-127 > > Anyway, I will take a look if it has any chance to overflow. It could in theory be alternate CPUs as comma separated list. So it's would get interesting around 500-1000 cpus (guessing). Hopefully no one has that crazy a cpu numbering scheme but it's possible (note that cluster is fine for this, but I guess it might eventually happen for core-siblings list (cpus within a package). Shouldn't crash or anything like that but might terminate early. On sysfs file conversion, that got mentioned earlier but I forgot to remind Barry about it when he took this patch into his series. Sorry about that! Jonathan > > > thanks, > > > > greg k-h > > Thanks > Barry >
WARNING: multiple messages have this Message-ID (diff)
From: Jonathan Cameron <Jonathan.Cameron@Huawei.com> To: "Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com> Cc: Greg KH <gregkh@linuxfoundation.org>, "tim.c.chen@linux.intel.com" <tim.c.chen@linux.intel.com>, "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>, "peterz@infradead.org" <peterz@infradead.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>, "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: [RFC PATCH v5 1/4] topology: Represent clusters of CPUs within a die Date: Fri, 19 Mar 2021 09:36:16 +0000 [thread overview] Message-ID: <20210319093616.00001879@Huawei.com> (raw) In-Reply-To: <eb48302277f3436eb9899032e6b0bf1c@hisilicon.com> On Fri, 19 Mar 2021 06:57:08 +0000 "Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com> wrote: > > -----Original Message----- > > From: Greg KH [mailto:gregkh@linuxfoundation.org] > > Sent: Friday, March 19, 2021 7:35 PM > > To: Song Bao Hua (Barry Song) <song.bao.hua@hisilicon.com> > > Cc: tim.c.chen@linux.intel.com; catalin.marinas@arm.com; will@kernel.org; > > rjw@rjwysocki.net; vincent.guittot@linaro.org; bp@alien8.de; > > tglx@linutronix.de; mingo@redhat.com; lenb@kernel.org; peterz@infradead.org; > > dietmar.eggemann@arm.com; rostedt@goodmis.org; bsegall@google.com; > > mgorman@suse.de; msys.mizuma@gmail.com; valentin.schneider@arm.com; Jonathan > > Cameron <jonathan.cameron@huawei.com>; juri.lelli@redhat.com; > > mark.rutland@arm.com; sudeep.holla@arm.com; aubrey.li@linux.intel.com; > > linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; > > linux-acpi@vger.kernel.org; x86@kernel.org; xuwei (O) <xuwei5@huawei.com>; > > Zengtao (B) <prime.zeng@hisilicon.com>; guodong.xu@linaro.org; yangyicong > > <yangyicong@huawei.com>; Liguozhu (Kenneth) <liguozhu@hisilicon.com>; > > linuxarm@openeuler.org; hpa@zytor.com > > Subject: Re: [RFC PATCH v5 1/4] topology: Represent clusters of CPUs within > > a die > > > > On Fri, Mar 19, 2021 at 05:16:15PM +1300, Barry Song wrote: > > > diff --git a/Documentation/admin-guide/cputopology.rst > > b/Documentation/admin-guide/cputopology.rst > > > index b90dafc..f9d3745 100644 > > > --- a/Documentation/admin-guide/cputopology.rst > > > +++ b/Documentation/admin-guide/cputopology.rst > > > @@ -24,6 +24,12 @@ core_id: > > > identifier (rather than the kernel's). The actual value is > > > architecture and platform dependent. > > > > > > +cluster_id: > > > + > > > + the Cluster ID of cpuX. Typically it is the hardware platform's > > > + identifier (rather than the kernel's). The actual value is > > > + architecture and platform dependent. > > > + > > > book_id: > > > > > > the book ID of cpuX. Typically it is the hardware platform's > > > @@ -56,6 +62,14 @@ package_cpus_list: > > > human-readable list of CPUs sharing the same physical_package_id. > > > (deprecated name: "core_siblings_list") > > > > > > +cluster_cpus: > > > + > > > + internal kernel map of CPUs within the same cluster. > > > + > > > +cluster_cpus_list: > > > + > > > + human-readable list of CPUs within the same cluster. > > > + > > > die_cpus: > > > > > > internal kernel map of CPUs within the same die. > > > > Why are these sysfs files in this file, and not in a Documentation/ABI/ > > file which can be correctly parsed and shown to userspace? > > Well. Those ABIs have been there for much a long time. It is like: > > [root@ceph1 topology]# ls > core_id core_siblings core_siblings_list physical_package_id thread_siblings thread_siblings_list > [root@ceph1 topology]# pwd > /sys/devices/system/cpu/cpu100/topology > [root@ceph1 topology]# cat core_siblings_list > 64-127 > [root@ceph1 topology]# > > > > > Any chance you can fix that up here as well? > > Yes. we will send a separate patch to address this, which won't > be in this patchset. This patchset will base on that one. > > > > > Also note that "list" is not something that goes in sysfs, sysfs is "one > > value per file", and a list is not "one value". How do you prevent > > overflowing the buffer of the sysfs file if you have a "list"? > > > > At a glance, the list is using "-" rather than a real list > [root@ceph1 topology]# cat core_siblings_list > 64-127 > > Anyway, I will take a look if it has any chance to overflow. It could in theory be alternate CPUs as comma separated list. So it's would get interesting around 500-1000 cpus (guessing). Hopefully no one has that crazy a cpu numbering scheme but it's possible (note that cluster is fine for this, but I guess it might eventually happen for core-siblings list (cpus within a package). Shouldn't crash or anything like that but might terminate early. On sysfs file conversion, that got mentioned earlier but I forgot to remind Barry about it when he took this patch into his series. Sorry about that! Jonathan > > > thanks, > > > > greg k-h > > Thanks > Barry > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-03-19 9:38 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-19 4:16 [RFC PATCH v5 0/4] scheduler: expose the topology of clusters and add cluster scheduler Barry Song 2021-03-19 4:16 ` Barry Song 2021-03-19 4:16 ` [RFC PATCH v5 1/4] topology: Represent clusters of CPUs within a die Barry Song 2021-03-19 4:16 ` Barry Song 2021-03-19 6:35 ` Greg KH 2021-03-19 6:35 ` Greg KH 2021-03-19 6:57 ` Song Bao Hua (Barry Song) 2021-03-19 6:57 ` Song Bao Hua (Barry Song) 2021-03-19 9:36 ` Jonathan Cameron [this message] 2021-03-19 9:36 ` Jonathan Cameron 2021-03-19 10:01 ` Greg KH 2021-03-19 10:01 ` Greg KH 2021-04-20 3:30 ` Song Bao Hua (Barry Song) 2021-04-20 3:30 ` Song Bao Hua (Barry Song) 2021-04-21 4:06 ` Song Bao Hua (Barry Song) 2021-04-21 4:06 ` Song Bao Hua (Barry Song) 2021-03-19 4:16 ` [RFC PATCH v5 2/4] scheduler: add scheduler level for clusters Barry Song 2021-03-19 4:16 ` Barry Song 2021-03-19 4:16 ` [RFC PATCH v5 3/4] scheduler: scan idle cpu in cluster before scanning the whole llc Barry Song 2021-03-19 4:16 ` Barry Song 2021-03-19 21:39 ` Song Bao Hua (Barry Song) 2021-03-19 21:39 ` Song Bao Hua (Barry Song) 2021-03-19 4:16 ` [RFC PATCH v5 4/4] scheduler: Add cluster scheduler level for x86 Barry Song 2021-03-19 4:16 ` Barry Song 2021-03-23 22:50 ` Tim Chen 2021-03-23 22:50 ` Tim Chen 2021-03-23 23:21 ` Song Bao Hua (Barry Song) 2021-03-23 23:21 ` Song Bao Hua (Barry Song) 2021-04-20 18:31 ` Tim Chen 2021-04-20 18:31 ` Tim Chen 2021-04-20 22:31 ` Song Bao Hua (Barry Song) 2021-04-20 22:31 ` Song Bao Hua (Barry Song) 2021-03-31 10:07 ` Song Bao Hua (Barry Song) 2021-03-31 10:07 ` Song Bao Hua (Barry Song)
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