All of lore.kernel.org
 help / color / mirror / Atom feed
From: Nathan Lynch <ntl@pobox.com>
To: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Corey Ashford <cjashfor@linux.vnet.ibm.com>,
	Andi Kleen <andi@firstfloor.org>, Ingo Molnar <mingo@elte.hu>,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Stephane Eranian <eranian@googlemail.com>,
	Eric Dumazet <dada1@cosmosbay.com>,
	Robert Richter <robert.richter@amd.com>,
	Arjan van de Veen <arjan@infradead.org>,
	Peter Anvin <hpa@zytor.com>,
	"David S. Miller" <davem@davemloft.net>,
	Maynard Johnson <mpjohn@us.ibm.com>,
	carll@us.ibm.com
Subject: Re: Performance counter API review was [patch] Performance Counters for Linux, v3
Date: Tue, 3 Feb 2009 20:32:36 -0600	[thread overview]
Message-ID: <20090204023236.GH6913@localdomain> (raw)
In-Reply-To: <18824.64228.358045.890823@cargo.ozlabs.ibm.com>

Paul Mackerras wrote:
>
> By the way, how does userspace get to know about cpus being added or
> removed?  Is there a better way than continually reading
> /sys/devices/system/cpu/online?

The kernel generates uevents for cpu online and offline operations;
you can see them with udevmonitor.  Not sure how you get those events
to an arbitrary application, though.  Alternatively you can set an
inotify watch on e.g. /sys/devices/system/cpu/cpu1/online (at least it
seems to work here).

  reply	other threads:[~2009-02-04  2:33 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-12-11 15:52 [patch] Performance Counters for Linux, v3 Ingo Molnar
2008-12-11 18:02 ` Vince Weaver
2008-12-12  8:25   ` Peter Zijlstra
2008-12-12  8:35     ` stephane eranian
2008-12-12  8:51       ` Peter Zijlstra
2008-12-12  9:00         ` Peter Zijlstra
2008-12-12  9:07           ` Ingo Molnar
2008-12-12  8:59     ` stephane eranian
2008-12-12  9:23       ` Peter Zijlstra
2008-12-12 10:21         ` Robert Richter
2008-12-12 10:59           ` Christoph Hellwig
2008-12-12 11:35             ` Robert Richter
2008-12-12 16:45         ` Chris Friesen
2008-12-12 17:42         ` stephane eranian
2008-12-12 18:01           ` stephane eranian
2008-12-12 19:45             ` Chris Friesen
2008-12-15 14:50               ` stephane eranian
2008-12-15 22:32                 ` Chris Friesen
2008-12-17  7:45                   ` stephane eranian
2008-12-14 23:13             ` Ingo Molnar
2008-12-15  0:37               ` Paul Mackerras
2008-12-15 12:58                 ` stephane eranian
2008-12-15 14:42                 ` stephane eranian
2008-12-15 20:58               ` stephane eranian
2008-12-15 22:53               ` Paul Mackerras
2008-12-13 11:17           ` Peter Zijlstra
2008-12-13 13:48             ` Henrique de Moraes Holschuh
2008-12-13 17:44             ` stephane eranian
2008-12-14  1:02             ` Paul Mackerras
2008-12-14 22:37               ` Ingo Molnar
2008-12-15  0:50                 ` Paul Mackerras
2008-12-15 13:02                   ` stephane eranian
2008-12-12 17:03     ` Samuel Thibault
2008-12-12 17:11       ` Peter Zijlstra
2008-12-12 18:18     ` Vince Weaver
2008-12-11 18:35 ` Andrew Morton
2008-12-12  6:22   ` Ingo Molnar
2008-12-11 19:11 ` Tony Luck
2008-12-11 19:34   ` Ingo Molnar
2008-12-12  8:29     ` Peter Zijlstra
2008-12-12  8:54       ` Ingo Molnar
2008-12-12 13:42       ` Andi Kleen
2008-12-14 14:51 ` Performance counter API review was " Andi Kleen
2009-02-02 20:03   ` Corey Ashford
2009-02-02 20:33     ` Peter Zijlstra
2009-02-03 16:53       ` Maynard Johnson
2009-02-04  2:18       ` Paul Mackerras
2009-02-04  2:32         ` Nathan Lynch [this message]
2009-02-04  8:45         ` Peter Zijlstra
2009-02-04 10:47           ` Paul Mackerras
2009-02-04 10:51             ` Peter Zijlstra

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=20090204023236.GH6913@localdomain \
    --to=ntl@pobox.com \
    --cc=a.p.zijlstra@chello.nl \
    --cc=akpm@linux-foundation.org \
    --cc=andi@firstfloor.org \
    --cc=arjan@infradead.org \
    --cc=carll@us.ibm.com \
    --cc=cjashfor@linux.vnet.ibm.com \
    --cc=dada1@cosmosbay.com \
    --cc=davem@davemloft.net \
    --cc=eranian@googlemail.com \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@elte.hu \
    --cc=mpjohn@us.ibm.com \
    --cc=paulus@samba.org \
    --cc=robert.richter@amd.com \
    --cc=tglx@linutronix.de \
    /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.