linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: baruch@tkos.co.il (Baruch Siach)
To: linux-arm-kernel@lists.infradead.org
Subject: sched_clock always 0 and no process time accounting with 3.11-rc1
Date: Wed, 17 Jul 2013 12:12:09 +0300	[thread overview]
Message-ID: <20130717091209.GL6950@tarshish> (raw)
In-Reply-To: <20130717090354.GK24642@n2100.arm.linux.org.uk>

Hi Russell,

On Wed, Jul 17, 2013 at 10:03:55AM +0100, Russell King - ARM Linux wrote:
> On Wed, Jul 17, 2013 at 09:19:25AM +0300, Baruch Siach wrote:
> > Apparently the expression '(1 << 32)' evaluates to 1 on xtensa cross gcc, and 
> > x86_84 native gcc. According to my limited understanding, the C compiler is 
> > allowed to do so. This caused sched_clock_32() to return constant 0. I wonder 
> > how it didn't bite the ARM people who are using this code from quite some time 
> > (added LAKL to CC).
> 
> It (a) used to be only 32-bit, and (b) <<32 on ARM evaluates to zero in
> a 32-bit context (it's not a rotate).
> 
> Patch looks fine.

Thanks for the confirmation, I'll take it as an ack if you don't mind.

> I wonder who takes it... after all, I used to look
> after that code (after all, I'm the author of it), but now I guess as
> it's been moved under kernel/time, it's someone elses responsibility.

Since the code move went through the tree of the timekeepers, John Stultz and 
Thomas Gleixner, I guess they should handle it.

baruch

-- 
     http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -

  reply	other threads:[~2013-07-17  9:12 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAMo8BfLO31GgMMA_hENr0xm=qaUz3EVLtaQ8hewiQHdbV+s6sA@mail.gmail.com>
2013-07-17  6:19 ` sched_clock always 0 and no process time accounting with 3.11-rc1 Baruch Siach
2013-07-17  6:39   ` Max Filippov
2013-07-17  6:47     ` [Linux-Xtensa] " Baruch Siach
2013-07-17  7:02       ` Chris Zankel
2013-07-17  7:14         ` Baruch Siach
2013-07-17  9:03   ` Russell King - ARM Linux
2013-07-17  9:12     ` Baruch Siach [this message]
2013-07-17  9:15       ` Russell King - ARM Linux
2013-07-17 15:15   ` [Linux-Xtensa] " Marc Gauthier
2013-07-17 15:24     ` Russell King - ARM Linux
2013-07-17 16:17       ` Marc Gauthier

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=20130717091209.GL6950@tarshish \
    --to=baruch@tkos.co.il \
    --cc=linux-arm-kernel@lists.infradead.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).