All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ananya Muddukrishna <ananya@kth.se>
To: linux-numa@vger.kernel.org
Subject: numa_alloc_interleaved and expectation of round-robin allocation
Date: Thu, 5 Jan 2012 09:31:00 +0000 (UTC)	[thread overview]
Message-ID: <loom.20120105T101458-346@post.gmane.org> (raw)

Hi,

I am using numactl-2.0.8-rc3 on a large server machine with 8 NUMA nodes and 
8Gbyte of memory per node.

I ran a test application compiled using numactl-2.0.8-rc3/test/tshared.c. I 
understand that this piece of code allocates memory pages as interleaved on all 
numa nodes. Later the application gets the memory policy 
(MPOL_F_NODE|MPOL_F_ADDR) for the pages allocated and prints out deviations from 
round-robin allocation if any.

In my tests I find a huge bias and deviation from the expected round-robin 
allocation. Around 90% of the pages are allocated on node#0. I tried 
numa_set_strict(1) but numa_alloc_interleaved does not honor this flag in 
agreement with the documentation.

Please explain this behavior to me. Must I patch numactl to enforce round-robin 
strictness?

Thanks!
-- Ananya


             reply	other threads:[~2012-01-05  9:31 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-05  9:31 Ananya Muddukrishna [this message]
2012-01-05 16:53 ` numa_alloc_interleaved and expectation of round-robin allocation Cliff Wickman

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=loom.20120105T101458-346@post.gmane.org \
    --to=ananya@kth.se \
    --cc=linux-numa@vger.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.