From: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
To: Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>
Cc: Pavel Machek <pavel-+ZI9xUNit7I@public.gmane.org>,
Roland Dreier <rdreier-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>,
Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
Anton Blanchard <anton-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
general-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org,
akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org,
torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org,
Jeff Squyres <jsquyres-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
Subject: Re: [ofa-general] Re: [GIT PULL] please pull ummunotify
Date: Mon, 12 Oct 2009 13:30:48 -0600 [thread overview]
Message-ID: <20091012193048.GA20313@obsidianresearch.com> (raw)
In-Reply-To: <20091012181944.GF17138-X9Un+BFzKDI@public.gmane.org>
On Mon, Oct 12, 2009 at 08:19:44PM +0200, Ingo Molnar wrote:
> > After that point the scheme is perfectly lossless.
>
> Well if it can OOM it's not lossless, obviously. You just define "event
> loss" to be equivalent to "Destruction of the universe." ;-)
It can't OOM once the ummunotify registration is done - when an event
occurs it doesn't allocate any memory and it doesn't loose events.
It has the same problem as perf - you either bound the number/size of
filters, or let user space allocate filters until the box OOMs. perf
has the additonal problem that even with filters you can still loose
events if the event ring overflows.
Jason
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WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Pavel Machek <pavel@ucw.cz>, Roland Dreier <rdreier@cisco.com>,
Peter Zijlstra <peterz@infradead.org>,
linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
Paul Mackerras <paulus@samba.org>,
Anton Blanchard <anton@samba.org>,
general@lists.openfabrics.org, akpm@linux-foundation.org,
torvalds@linux-foundation.org, Jeff Squyres <jsquyres@cisco.com>
Subject: Re: [ofa-general] Re: [GIT PULL] please pull ummunotify
Date: Mon, 12 Oct 2009 13:30:48 -0600 [thread overview]
Message-ID: <20091012193048.GA20313@obsidianresearch.com> (raw)
In-Reply-To: <20091012181944.GF17138@elte.hu>
On Mon, Oct 12, 2009 at 08:19:44PM +0200, Ingo Molnar wrote:
> > After that point the scheme is perfectly lossless.
>
> Well if it can OOM it's not lossless, obviously. You just define "event
> loss" to be equivalent to "Destruction of the universe." ;-)
It can't OOM once the ummunotify registration is done - when an event
occurs it doesn't allocate any memory and it doesn't loose events.
It has the same problem as perf - you either bound the number/size of
filters, or let user space allocate filters until the box OOMs. perf
has the additonal problem that even with filters you can still loose
events if the event ring overflows.
Jason
next prev parent reply other threads:[~2009-10-12 19:30 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-11 4:38 [GIT PULL] please pull ummunotify Roland Dreier
2009-09-11 4:38 ` Roland Dreier
2009-09-15 11:34 ` Pavel Machek
[not found] ` <20090915113434.GF1328-+ZI9xUNit7I@public.gmane.org>
2009-09-15 14:57 ` [ofa-general] " Roland Dreier
2009-09-15 14:57 ` Roland Dreier
[not found] ` <ada7hw0gsqz.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-28 20:49 ` Pavel Machek
2009-09-28 20:49 ` Pavel Machek
[not found] ` <20090928204923.GA1960-I/5MKhXcvmPrBKCeMvbIDA@public.gmane.org>
2009-09-28 21:40 ` Jason Gunthorpe
2009-09-28 21:40 ` Jason Gunthorpe
[not found] ` <aday6omhz9d.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-11 5:56 ` KOSAKI Motohiro
2009-09-11 5:56 ` KOSAKI Motohiro
2009-09-11 6:03 ` [ofa-general] " Roland Dreier
2009-09-11 6:03 ` Roland Dreier
[not found] ` <adatyzahvbm.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-11 6:11 ` KOSAKI Motohiro
2009-09-11 6:11 ` KOSAKI Motohiro
[not found] ` <20090911150552.DB68.A69D9226-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2009-09-11 16:42 ` Gleb Natapov
2009-09-11 16:42 ` Gleb Natapov
2009-09-11 6:15 ` Brice Goglin
[not found] ` <4AA9EAF7.5010401-MZpvjPyXg2s@public.gmane.org>
2009-09-11 6:21 ` KOSAKI Motohiro
2009-09-11 6:21 ` KOSAKI Motohiro
2009-09-11 6:22 ` Roland Dreier
2009-09-11 6:22 ` Roland Dreier
2009-09-11 6:40 ` [ofa-general] " Jason Gunthorpe
2009-09-11 6:40 ` Jason Gunthorpe
[not found] ` <20090911064019.GZ4973-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2009-09-11 16:58 ` Roland Dreier
2009-09-11 16:58 ` Roland Dreier
[not found] ` <adaljklifkt.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-15 7:03 ` KOSAKI Motohiro
2009-09-15 7:03 ` KOSAKI Motohiro
2009-09-15 8:27 ` Roland Dreier
2009-09-15 8:27 ` Roland Dreier
2009-09-15 12:38 ` Jeff Squyres
2009-09-15 12:38 ` Jeff Squyres
2009-09-16 16:30 ` Roland Dreier
2009-09-16 16:30 ` Roland Dreier
2009-09-16 16:40 ` [ofa-general] " Linus Torvalds
2009-09-16 16:40 ` Linus Torvalds
2009-09-17 11:30 ` Peter Zijlstra
2009-09-17 11:30 ` Peter Zijlstra
2009-09-17 14:24 ` [ofa-general] " Roland Dreier
[not found] ` <adafxalejiq.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-17 14:32 ` Roland Dreier
2009-09-17 14:32 ` Roland Dreier
[not found] ` <adaab0tej5c.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-17 14:49 ` Peter Zijlstra
2009-09-17 14:49 ` Peter Zijlstra
2009-09-17 15:03 ` Roland Dreier
2009-09-17 15:03 ` Roland Dreier
[not found] ` <adazl8td35u.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-17 15:22 ` Peter Zijlstra
2009-09-17 15:22 ` Peter Zijlstra
2009-09-17 15:45 ` Roland Dreier
2009-09-17 15:45 ` Roland Dreier
[not found] ` <adatyz1d17q.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-09-18 11:50 ` Ingo Molnar
2009-09-18 11:50 ` Ingo Molnar
2009-09-29 17:13 ` Pavel Machek
2009-09-29 17:13 ` Pavel Machek
[not found] ` <20090929171332.GD14405-I/5MKhXcvmPrBKCeMvbIDA@public.gmane.org>
2009-09-30 9:44 ` Ingo Molnar
2009-09-30 9:44 ` Ingo Molnar
[not found] ` <20090930094456.GD24621-X9Un+BFzKDI@public.gmane.org>
2009-09-30 16:02 ` Jason Gunthorpe
2009-09-30 16:02 ` Jason Gunthorpe
[not found] ` <20090930160232.GZ22310-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2009-10-12 18:19 ` Ingo Molnar
2009-10-12 18:19 ` Ingo Molnar
[not found] ` <20091012181944.GF17138-X9Un+BFzKDI@public.gmane.org>
2009-10-12 19:30 ` Jason Gunthorpe [this message]
2009-10-12 19:30 ` Jason Gunthorpe
2009-10-12 20:20 ` Ingo Molnar
[not found] ` <20091012202046.GA7648-X9Un+BFzKDI@public.gmane.org>
2009-10-13 4:05 ` Jason Gunthorpe
2009-10-13 4:05 ` Jason Gunthorpe
2009-10-13 6:40 ` Ingo Molnar
[not found] ` <20091013064006.GC9470-X9Un+BFzKDI@public.gmane.org>
2009-10-13 16:27 ` Jason Gunthorpe
2009-10-13 16:27 ` Jason Gunthorpe
2009-10-13 5:43 ` Brice Goglin
[not found] ` <4AD41373.8010108-MZpvjPyXg2s@public.gmane.org>
2009-10-13 6:38 ` Ingo Molnar
2009-10-13 6:38 ` Ingo Molnar
2009-09-30 17:06 ` Roland Dreier
2009-09-30 17:06 ` Roland Dreier
2009-10-02 16:32 ` Roland Dreier
2009-10-02 16:32 ` Roland Dreier
[not found] ` <ada3a61rc3j.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-10-02 20:45 ` Pavel Machek
2009-10-02 20:45 ` Pavel Machek
2009-10-07 22:34 ` Roland Dreier
2009-10-07 22:34 ` Roland Dreier
[not found] ` <ada3a5uq1dk.fsf-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
2009-10-12 17:33 ` Peter Zijlstra
2009-10-12 17:33 ` Peter Zijlstra
2009-09-17 14:43 ` Peter Zijlstra
2009-09-17 14:43 ` Peter Zijlstra
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