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From: Peter Waechtler <pwaechtler@mac.com>
To: David Schwartz <davids@webmaster.com>
Cc: <linux-kernel@vger.kernel.org>
Subject: Re: [ANNOUNCE] Native POSIX Thread Library 0.1
Date: Wed, 25 Sep 2002 01:16:58 +0200	[thread overview]
Message-ID: <B9100B20-D013-11D6-8873-00039387C942@mac.com> (raw)
In-Reply-To: <20020924201908.AAA16336@shell.webmaster.com@whenever>

Am Dienstag den, 24. September 2002, um 22:19, schrieb David Schwartz:

>
>> The effect of M:N on UP systems should be even more clear. Your
>> multithreaded apps can't profit of parallelism but they do not
>> add load to the system scheduler. The drawback: more syscalls
>> (I think about removing the need for
>> flags=fcntl(GETFLAGS);fcntl(fd,NONBLOCK);write(fd);fcntl(fd,flags))
>
> 	The main reason I write multithreaded apps for single CPU systems 
> is to
> protect against ambush. Consider, for example, a web server. Someone 
> sends it
> an obscure request that triggers some code that's never run before and 
> has to
> fault in. If my application were single-threaded, no work could be done 
> until
> that page faulted in from disk. This is why select-loop and poll-loop 
> type
> servers are bursty.

With the current NGPT design your threads would be blocked (all that are 
scheduled
one this kernel vehicle).

With Scheduler Activations this could also be avoided.
The thread scheduler could get an upcall - but this will stay theory for 
a long
time on Linux.
But this is a somewhat far fetched example (for arguing for 1:1), isn't 
it?

There are other means of DoS..




  parent reply	other threads:[~2002-09-24 23:12 UTC|newest]

Thread overview: 124+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-09-22 18:55 [ANNOUNCE] Native POSIX Thread Library 0.1 Peter Waechtler
2002-09-22 21:32 ` Larry McVoy
2002-09-23 10:05   ` Bill Davidsen
2002-09-23 11:55     ` Peter Waechtler
2002-09-23 19:14       ` Bill Davidsen
2002-09-29 23:26         ` Buddy Lumpkin
2002-09-30 14:54           ` Corey Minyard
2002-09-23 15:30     ` Larry McVoy
2002-09-23 19:44       ` Olivier Galibert
2002-09-23 19:48       ` Bill Davidsen
2002-09-23 20:32         ` Ingo Molnar
2002-09-24  0:03           ` Andy Isaacson
2002-09-24  0:10             ` Jeff Garzik
2002-09-24  0:14               ` Andy Isaacson
2002-09-24  5:53             ` Ingo Molnar
2002-09-24 20:34             ` David Schwartz
2002-09-24  7:12           ` Thunder from the hill
2002-09-24  7:30             ` Ingo Molnar
2002-09-23 22:35         ` Mark Mielke
2002-09-23 19:59       ` Peter Waechtler
2002-09-23 20:36         ` Ingo Molnar
2002-09-23 21:08           ` Peter Wächtler
2002-09-23 22:44             ` Mark Mielke
2002-09-23 23:01               ` Bill Huey
2002-09-23 23:11                 ` Mark Mielke
2002-09-24  0:21                   ` Bill Huey
2002-09-24  3:20                     ` Mark Mielke
2002-09-23 23:57           ` Andy Isaacson
2002-09-24  6:32             ` 1:1 threading vs. scheduler activations (was: Re: [ANNOUNCE] Native POSIX Thread Library 0.1) Ingo Molnar
2002-09-25  3:08               ` Bill Huey
2002-09-24 18:10             ` [ANNOUNCE] Native POSIX Thread Library 0.1 Christoph Hellwig
2002-09-23 21:32       ` Bill Huey
2002-09-23 21:41       ` dean gaudet
2002-09-23 22:10         ` Bill Huey
2002-09-23 22:56         ` Mark Mielke
2002-09-24 10:02       ` Nikita Danilov
2002-09-23 21:22     ` Bill Huey
2002-09-23 21:03 ` Bill Huey
2002-09-24 12:03   ` Michael Sinz
2002-09-24 13:40     ` Peter Svensson
2002-09-24 14:20       ` Michael Sinz
2002-09-24 14:50         ` Offtopic: (was Re: [ANNOUNCE] Native POSIX Thread Library 0.1) Peter Svensson
2002-09-24 15:19           ` Mark Veltzer
2002-09-24 17:29             ` Rik van Riel
2002-09-25 18:57               ` Mark Mielke
2002-09-25 19:04                 ` Rik van Riel
2002-09-25 19:29                   ` Mark Veltzer
2002-09-25 19:23                     ` Rik van Riel
2002-09-24 16:31           ` Rik van Riel
2002-09-24 18:49             ` Michael Sinz
2002-09-24 19:12               ` PATCH: per user fair scheduler 2.4.19 (cleaned up, thanks hch) (was: Re: Offtopic: (was Re: [ANNOUNCE] Native POSIX Thread Library 0.1)) Rik van Riel
2002-09-24 20:19 ` [ANNOUNCE] Native POSIX Thread Library 0.1 David Schwartz
2002-09-24 21:10   ` Chris Friesen
2002-09-24 21:22     ` Rik van Riel
2002-09-24 21:35       ` Roberto Peon
2002-09-24 21:35       ` Chris Friesen
2002-09-25 19:02     ` David Schwartz
2002-09-24 23:16   ` Peter Waechtler [this message]
2002-09-24 23:23     ` Rik van Riel
2002-09-25 19:05     ` David Schwartz
     [not found] <987738530@toto.iv>
2002-09-24  2:48 ` Peter Chubb
2002-09-24  3:37   ` Mark Mielke
  -- strict thread matches above, loose matches on Subject: below --
2002-09-23 16:36 Matthias Urlichs
2002-09-20  7:46 Joerg Pommnitz
2002-09-20  0:41 Ulrich Drepper
2002-09-20  0:51 ` William Lee Irwin III
2002-09-20  1:35   ` Ulrich Drepper
2002-09-20  1:42     ` William Lee Irwin III
2002-09-20  1:56 ` Larry McVoy
2002-09-20  2:01 ` Rik van Riel
2002-09-20  2:15   ` Benjamin LaHaise
2002-09-20  2:40     ` Dave Hansen
2002-09-20  2:47     ` William Lee Irwin III
2002-09-20  2:17   ` Larry McVoy
2002-09-20  2:24     ` Rik van Riel
2002-09-20  2:32       ` Ulrich Drepper
2002-09-20  6:01       ` Linus Torvalds
2002-09-20  8:02         ` Ingo Molnar
2002-09-20  2:23   ` Anton Blanchard
2002-09-20  9:53 ` Padraig Brady
2002-09-20 13:28   ` Robert Love
2002-09-20 16:01     ` Bill Davidsen
2002-09-20  9:54 ` Adrian Bunk
2002-09-20 10:53   ` Ingo Molnar
2002-09-20 19:04   ` Ulrich Drepper
2002-09-20 23:06     ` J.A. Magallon
2002-09-20 23:33       ` Ulrich Drepper
2002-09-20 23:42         ` J.A. Magallon
2002-09-20 10:20 ` Bill Huey
2002-09-20 10:47   ` Ingo Molnar
2002-09-20 12:06     ` Bill Huey
2002-09-20 16:20       ` Ingo Molnar
2002-09-20 21:50         ` Bill Huey
2002-09-20 22:30           ` dean gaudet
2002-09-20 23:11             ` Bill Huey
2002-09-21  3:38               ` dean gaudet
2002-09-21  4:01                 ` Bill Huey
2002-09-21  5:06                   ` Ingo Molnar
2002-09-20 23:45           ` Bill Huey
2002-09-21  4:58             ` Ingo Molnar
2002-09-22  2:51               ` Bill Huey
2002-09-21  4:48           ` Ingo Molnar
2002-09-22  1:38             ` Bill Huey
2002-09-22 13:38           ` Bill Davidsen
2002-09-22 18:41             ` Eric W. Biederman
2002-09-22 22:13               ` dean gaudet
2002-09-26 17:21                 ` Alan Cox
2002-09-23  0:11               ` Bill Huey
2002-09-24 16:07                 ` Eric W. Biederman
2002-09-24 23:21                   ` Bill Huey
2002-09-25  3:06                     ` Eric W. Biederman
2002-09-23 21:12             ` Bill Huey
2002-09-20 10:35 ` Luca Barbieri
2002-09-20 11:19   ` Ingo Molnar
2002-09-20 18:40     ` Roland McGrath
2002-09-20 21:21       ` Luca Barbieri
2002-09-20 12:37 ` jlnance
2002-09-20 16:42   ` Ingo Molnar
2002-09-24  0:40     ` Rusty Russell
2002-09-24  5:47       ` Ingo Molnar
2002-09-24  6:15         ` Rusty Russell
2002-09-20 15:43 ` Bill Davidsen
2002-09-20 16:15   ` Jakub Jelinek
2002-09-20 17:16     ` Bill Davidsen

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