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* Re: [9fans] 8 cores
@ 2008-07-17 12:41 erik quanstrom
  2008-07-17 12:56 ` William Josephson
  2008-07-17 12:58 ` ron minnich
  0 siblings, 2 replies; 42+ messages in thread
From: erik quanstrom @ 2008-07-17 12:41 UTC (permalink / raw)
  To: rvs, 9fans

> > > I could imagine that databases use mmap() havily
> >
> > it's a little mystery for me why they would do that since it's slower (or ought to be),
>
> slower compared to what? I'd expect the biggest slowdown for
> read()/write() be not the price of a syscall, but what you
> pay for copying data in/out of the kernel. With mmap() there's
> no copying.

as you've pointed out, performance-wise it's not copying vs. nothing
it's copying vs page faults and trips through the vm code.
i would think playing vm games (as linus likes to say) would make
scheduling on mp harder

- erik



^ permalink raw reply	[flat|nested] 42+ messages in thread
* [9fans] 8 cores
@ 2008-07-15 22:28 erik quanstrom
  2008-07-15 22:27 ` Benjamin Huntsman
                   ` (3 more replies)
  0 siblings, 4 replies; 42+ messages in thread
From: erik quanstrom @ 2008-07-15 22:28 UTC (permalink / raw)
  To: 9fans

coming as no suprise, the pc port of plan 9
does work just fine with 8 cores.

mpls; cat /dev/sysstat
          0       14271      213501        3399        1116           0           0           0          99           0
          1        9116      105177        2279         812           0           0           0          99           0
          2       15142      106240        3578        1298           0           0           0          99           0
          3        9529      102845        2663         644           0           0           0          99           0
          4       15035      108986        3717        1285           0           0           0          99           0
          5        9054      105184        2198         744           0           0           0          99           0
          6       15222      106532        3633        1217           0           0           0          99           0
          7        9547      103239        2525         868           0           0           0          99           0

this machine has more processor cache (24mb)
than the entire unix room where i went to school.

and it's only ½ of a 1u chassis.  the other half,
stpaul, has an identical configuration.

- erik



^ permalink raw reply	[flat|nested] 42+ messages in thread

end of thread, other threads:[~2008-07-23 18:32 UTC | newest]

Thread overview: 42+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2008-07-17 12:41 [9fans] 8 cores erik quanstrom
2008-07-17 12:56 ` William Josephson
2008-07-17 12:58 ` ron minnich
2008-07-17 13:46   ` erik quanstrom
2008-07-17 14:06     ` ron minnich
  -- strict thread matches above, loose matches on Subject: below --
2008-07-15 22:28 erik quanstrom
2008-07-15 22:27 ` Benjamin Huntsman
2008-07-15 22:35 ` Williams, Mitch
2008-07-16  1:39   ` erik quanstrom
2008-07-16  5:12     ` Benjamin Huntsman
2008-07-16  7:00       ` sqweek
2008-07-16 12:54         ` Russ Cox
2008-07-16 11:37       ` C H Forsyth
2008-07-16 12:13         ` John Waters
2008-07-16 13:03           ` a
2008-07-16 13:44           ` Uriel
2008-07-16 13:55             ` John Waters
2008-07-16 14:16             ` Robert William Fuller
2008-07-16 13:07       ` erik quanstrom
2008-07-16 13:42         ` Uriel
2008-07-16 15:02         ` Benjamin Huntsman
2008-07-16 18:56           ` Uriel
2008-07-17  7:59             ` Kernel Panic
2008-07-17  9:07               ` Charles Forsyth
2008-07-17 10:04                 ` Kernel Panic
2008-07-17 10:14                 ` Roman V. Shaposhnik
2008-07-17 12:55                 ` ron minnich
2008-07-17 12:58                   ` William Josephson
2008-07-17 13:45                   ` erik quanstrom
2008-07-17 14:11                     ` ron minnich
2008-07-17 14:32                   ` Roman V. Shaposhnik
2008-07-17 13:32                 ` Paweł Lasek
2008-07-17 14:07                   ` Kernel Panic
2008-07-16 22:44       ` Iruata Souza
2008-07-17  8:38         ` Kernel Panic
2008-07-17 18:14           ` Iruata Souza
2008-07-23 11:42             ` matt
2008-07-23 18:32               ` Iruata Souza
2008-07-16  1:41 ` andrey mirtchovski
2008-07-16 20:38 ` Roman V. Shaposhnik
2008-07-17  2:09   ` erik quanstrom
2008-07-17 10:18     ` Roman V. Shaposhnik

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