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Date:      Mon, 26 Nov 2001 13:25:38 +0100
From:      Thiemo Nordenholz <nz@thiemo.net>
To:        freebsd-alpha@freebsd.org
Subject:   mprotect() takes quite long -- anyone knows this?
Message-ID:  <20011126132537.A10631@kiste.thiemo.net>

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Moin,

I run FreeBSD 4.4-RELEASE on an AXPpci33 board with 64MB of RAM. It runs
quite stable, but dead slow when executing commands. After a process is
running, it seems to work at normal speed (haven't really verified this,
though).

Investigation shows that most of the time is used up in an mprotect() system
call:


-=======================================================================-

74[thiemo@myg:~]> time w
 1:15PM  up 2 days, 12:16, 1 user, load averages: 0.04, 0.07, 0.02
 USER             TTY      FROM              LOGIN@  IDLE WHAT
 thiemo           p0       somewhere         11:28AM     - w
 0.882u 0.094s 0:00.99 97.9%     29+199k 0+0io 0pf+0w

then, from a "ktrace w":

77[thiemo@myg:~]> kdump -R | grep mprotect
 52860 w        0.004988 CALL  mprotect(0x160062000,0xc2000,0x7)
 52860 w        0.000581 RET   mprotect 0
 52860 w        0.865540 CALL  mprotect(0x160062000,0xc2000,0x5)
 52860 w        0.001066 RET   mprotect 0

-=======================================================================-

Isn't this a bit long for a syscall? What's going on here? Defective memory?
Other flaws? Just me being too impatioent? A week ago, the Alpha ran just
fine under OpenBSD 2.3 (old and bah) -- but I want to make it running
FreeBSD as well...

If you need more information, contact me, please -- and thanks for any
hints!

Cheers,
  Thiemo    
 

-- 
Thiemo Nordenholz          <nz@thiemo.net>              http://www.thiemo.net
"Computers are great at wasting time that would be otherwise be difficult to
waste."      -- Cliff Stoll

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