From: Brice Goglin <Brice.Goglin@inria.fr>
To: Peter Zijlstra <peterz@infradead.org>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, x86@kernel.org,
Len Brown <len.brown@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Sudeep Holla <sudeep.holla@arm.com>,
guohanjun@huawei.com, Will Deacon <will@kernel.org>,
linuxarm@huawei.com, valentin.schneider@arm.com
Subject: Re: [RFC PATCH] topology: Represent clusters of CPUs within a die.
Date: Mon, 19 Oct 2020 15:12:33 +0200 [thread overview]
Message-ID: <5d326ec1-88c6-e0ce-2280-a00c7b35a811@inria.fr> (raw)
In-Reply-To: <20201019125053.GM2628@hirez.programming.kicks-ass.net>
Le 19/10/2020 à 14:50, Peter Zijlstra a écrit :
> On Mon, Oct 19, 2020 at 01:32:26PM +0100, Jonathan Cameron wrote:
>> On Mon, 19 Oct 2020 12:35:22 +0200
>> Peter Zijlstra <peterz@infradead.org> wrote:
>>> I'm confused by all of this. The core level is exactly what you seem to
>>> want.
>> It's the level above the core, whether in an multi-threaded core
>> or a single threaded core. This may correspond to the level
>> at which caches are shared (typically L3). Cores are already well
>> represented via thread_siblings and similar. Extra confusion is that
>> the current core_siblings (deprecated) sysfs interface, actually reflects
>> the package level and ignores anything in between core and
>> package (such as die on x86)
> That seems wrong. core-mask should be whatever cores share L3. So on a
> Intel Core2-Quad (just to pick an example) you should have 4 CPU in a
> package, but only 2 CPUs for the core-mask.
>
> It just so happens that L3 and package were the same for a long while in
> x86 land, although recent chips started breaking that trend.
>
> And I know nothing about the core-mask being depricated; it's what the
> scheduler uses. It's not going anywhere.
Only the sysfs filenames are deprecated:
thread_siblings -> core_cpus
core_siblings -> package_cpus
New names reflect better what has been implemented/documented in the
past (core_siblings=package_cpus are processors with same physical
package id). And that's indeed different from the core-mask you are
talking about above with Core2-Quad (that one has never been exposed
anywhere in sysfs, except in the L3 cpumap).
Brice
next prev parent reply other threads:[~2020-10-19 13:12 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-16 15:27 [RFC PATCH] topology: Represent clusters of CPUs within a die Jonathan Cameron
2020-10-17 6:44 ` Greg Kroah-Hartman
2020-10-19 8:08 ` Jonathan Cameron
2020-10-19 10:00 ` Brice Goglin
2020-10-19 12:38 ` Jonathan Cameron
2020-10-19 10:01 ` Sudeep Holla
2020-10-19 13:14 ` Jonathan Cameron
2020-10-19 10:35 ` Peter Zijlstra
2020-10-19 12:32 ` Jonathan Cameron
2020-10-19 12:50 ` Peter Zijlstra
2020-10-19 13:12 ` Brice Goglin [this message]
2020-10-19 13:13 ` Morten Rasmussen
2020-10-19 13:10 ` Morten Rasmussen
2020-10-19 13:41 ` Jonathan Cameron
2020-10-19 14:16 ` Morten Rasmussen
2020-10-19 14:42 ` Brice Goglin
2020-10-19 15:30 ` Jonathan Cameron
2020-10-19 13:48 ` Valentin Schneider
2020-10-19 14:27 ` Jonathan Cameron
2020-10-19 15:51 ` Valentin Schneider
2020-10-19 16:00 ` Jonathan Cameron
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5d326ec1-88c6-e0ce-2280-a00c7b35a811@inria.fr \
--to=brice.goglin@inria.fr \
--cc=Jonathan.Cameron@huawei.com \
--cc=gregkh@linuxfoundation.org \
--cc=guohanjun@huawei.com \
--cc=len.brown@intel.com \
--cc=linux-acpi@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxarm@huawei.com \
--cc=peterz@infradead.org \
--cc=sudeep.holla@arm.com \
--cc=valentin.schneider@arm.com \
--cc=will@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).