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From: Fabio Riccardi <fabio@chromium.com>
To: unlisted-recipients:; (no To-header on input)@localhost.localdomain
Cc: linux-kernel@vger.kernel.org
Subject: Re: X15 alpha release: as fast as TUX but in user space (fwd)
Date: Wed, 02 May 2001 13:55:53 -0700	[thread overview]
Message-ID: <3AF07459.8D8ECD8E@chromium.com> (raw)
In-Reply-To: <Pine.LNX.4.33.0104290914260.14261-100000@twinlark.arctic.org> <200104292116.f3TLGhu07016@pachyderm.pa.dec.com> <20010502211800.X805@mea-ext.zmailer.org> <9cpnfj$ms3$1@penguin.transmeta.com>

>From my experience system calls are not an issue.

What costs a lot is moving data around, since modern CPUs spend most of their
time in memory/bus wait cycles...

 - Fabio

Linus Torvalds wrote:

> >I think that applies to all really high-performance servers.
>
> Note that it is definitely not always true.
>
> Linux system calls are reasonably light-weight.  And sometimes trying to
> avoid them ends up beaing _more_ work - because you might have to worry
> about synchronization and cache coherency in user mode.
>
> So the rule should be "avoid _unnecessary_ system calls".
>
>                 Linus
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/


  reply	other threads:[~2001-05-02 20:52 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-04-28 15:52 Ingo Molnar
2001-04-28 19:53 ` Andi Kleen
2001-04-28 22:56 ` Richard Gooch
2001-04-29  5:13   ` H. Peter Anvin
2001-04-29 11:14     ` Jeff Garzik
2001-04-29 16:21       ` dean gaudet
2001-04-29 20:19         ` H. Peter Anvin
2001-04-29 21:16         ` Jim Gettys
2001-04-29 21:40           ` H. Peter Anvin
2001-04-29 21:47             ` Jim Gettys
2001-05-02 18:18           ` Matti Aarnio
2001-05-02 19:34             ` Linus Torvalds
2001-05-02 20:55               ` Fabio Riccardi [this message]
2001-04-29 22:29         ` Richard Gooch
2001-04-30  7:02       ` David S. Miller
2001-04-30  7:29         ` H. Peter Anvin
2001-04-30  7:51         ` David S. Miller
2001-04-30 14:56         ` Jonathan Lundell
2001-04-29 11:27     ` David S. Miller
2001-04-29 13:32       ` Ingo Oeser
2001-04-29 18:48       ` Richard Gooch
2001-04-29 18:55         ` Gregory Maxwell
2001-04-29 19:02         ` Richard Gooch
2001-04-29 19:47           ` Gregory Maxwell
2001-04-29 19:54           ` Richard Gooch
2001-04-29 20:11         ` Ingo Oeser
2001-04-29 20:18           ` Gregory Maxwell
2001-04-30  0:13             ` Andrea Arcangeli
2001-04-29 20:45           ` Arjan van de Ven
2001-04-29 22:20           ` Richard Gooch
2001-04-30 16:46           ` Alan Cox
2001-04-29 22:18         ` Richard Gooch
2001-04-29 19:38       ` Jamie Lokier
2001-04-29 23:53         ` Andrea Arcangeli
2001-04-30  8:42     ` Pavel Machek
2001-05-03  7:13       ` Kai Henningsen
2001-05-03  7:44         ` Keith Owens
2001-05-03 10:37           ` Ingo Oeser
2001-05-03 15:44           ` Gregory Maxwell
2001-05-07 19:04           ` Pavel Machek
2001-05-03  9:37         ` Alan Cox
2001-05-07 19:03           ` vsyscalls [was Re: X15 alpha release: as fast as TUX but in user space (fwd)] Pavel Machek
2001-05-03 12:23       ` X15 alpha release: as fast as TUX but in user space (fwd) Helge Hafting
2001-05-03 19:09         ` Pavel Machek
2001-05-03 19:50           ` agrawal
2001-05-07 19:07             ` vsyscallRe: " Pavel Machek
2001-05-03 20:19           ` Alan Cox
2001-05-03 20:41             ` Gregory Maxwell
2001-05-04  8:06               ` Pavel Machek
2001-05-04 17:31                 ` dean gaudet
2001-05-04  8:43             ` bert hubert
2001-05-02 10:52   ` Andi Kleen
2001-05-02 10:53     ` Ingo Molnar

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