-----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.
thanks,
greg k-h
Thanks Barry