From: Joel Schopp <jschopp@austin.ibm.com>
To: linuxppc-dev@ozlabs.org
Subject: [PATCHv2 0/2] Add max CPU nodes field to ibm,client-architecture call
Date: Mon, 01 Feb 2010 16:50:39 -0600 [thread overview]
Message-ID: <1265064639.5391.17.camel@jschopp-laptop> (raw)
In-Reply-To: <1263501508.4869.133.camel@jschopp-laptop>
Large NUMA machines require Linux to indicate support for more than 64
cpu cores. This is done through the ibm,client-architecture call, and
is documented in the PAPR. There is also another new field added to
indicate that the OS is Linux as a hint for possible future performance
settings.
The first patch attempts to statically initialize the number of
supported cores with NR_CPUS, the maximum Linux could boot if the cpus
did not have multi-threading (SMT). It can overestimate by the factor
of SMT. For instance on Power6 with 2 way SMT it would overestimate by
a factor of 2. The result of this overestimation is that Linux might
not be able boot all the cpus assigned to it, but would still boot
NR_CPUS worth of SMT threads.
The second patch adjusts for SMT by reading the device tree before
unflattening.
I've updated patch 1 from previous comments. Patch 1 can be taken on its
own if Patch 2 seems like overkill.
v2 - Updated patch 2 style and messages. Basic functionality is the
same as v1.
prev parent reply other threads:[~2010-02-01 22:50 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-14 20:38 [PATCH 0/2] Add max CPU nodes field to ibm,client-architecture call Joel Schopp
2010-01-14 20:40 ` [PATCH 1/2] Add static fields " Joel Schopp
2010-01-14 23:01 ` Joel Schopp
2010-01-15 2:51 ` Benjamin Herrenschmidt
2010-01-15 2:52 ` Benjamin Herrenschmidt
2010-02-01 22:50 ` [PATCHv2 " Joel Schopp
2010-01-14 20:41 ` [PATCH 2/2] Update ibm,client-architecture call field based on device tree Joel Schopp
2010-01-15 2:58 ` Benjamin Herrenschmidt
2010-02-01 22:51 ` [PATCHv2 " Joel Schopp
2010-02-02 3:48 ` Tony Breeds
2010-02-02 18:37 ` Joel Schopp
2010-02-04 3:27 ` Benjamin Herrenschmidt
2010-02-01 22:50 ` Joel Schopp [this message]
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=1265064639.5391.17.camel@jschopp-laptop \
--to=jschopp@austin.ibm.com \
--cc=linuxppc-dev@ozlabs.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).