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Date:      Mon, 1 Jul 2002 20:14:46 -0700 (PDT)
From:      Matthew Dillon <dillon@apollo.backplane.com>
To:        Julian Elischer <julian@elischer.org>, "Long, Scott" <Scott_Long@adaptec.com>, FreeBSD current users <current@FreeBSD.ORG>
Subject:   -current results (was something funny with soft updates?)
Message-ID:  <200207020314.g623Eke5038019@apollo.backplane.com>
References:  <Pine.BSF.4.21.0206281233500.75410-100000@InterJet.elischer.org> 

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    SMP builds are still producing panics every 2-4 buildworlds after the
    KSE commit, I'm still trying to track that down.  But I was able to
    complete the softupdates/non-softupdates test with a UP build of
    -current:


with softupdates (UP BUILD, CURRENT):
     3122.30 real      2360.70 user       532.54 sys
     3083.17 real      2361.14 user       529.53 sys
     3085.05 real      2361.59 user       529.32 sys

without softupdates (UP BUILD, CURRENT):
     3361.70 real      2365.23 user       535.50 sys
     3451.55 real      2368.22 user       537.26 sys
     3454.85 real      2369.42 user       536.69 sys
			^^^^^
    ~350 second dif	note user times
    for real.

    Included below are the original tests that were done under stable... the 
    overall 'real' times are NOT COMPARATIVE since the original tests were
    done with an SMP build, but the user times should be, and that is where
    I believe the major difference is occuring.  My guess is that the new
    GCC in -current is eating a massive amount of extra cpu.  It is eating
    over 2300 cpu seconds under -current and only 1400 under -stable while
    system time remains roughly comparable (remember that the interrupts
    are not charged to processes under -current).

    The difference in real time softupdate vs non-softupdates between
    current and stable is around 350 seconds under current, and 889
    seconds under stable.  This is fairly comparable when we consider that
    a good portion of the extra user time eaten in -current is absorbing 
    the stall delays for processes undergoing I/O that softupdates mostly
    fixes.

    My conclusion is that softupdates is working fine and (A) the new GCC
    is a whole lot less efficient then the old GCC and (B) user times are
    masking gains (due to high parallelism) that would otherwise be
    realized with softupdates.

:	(original tests under -stable)
:test1# cat x1		(SMP BUILD, STABLE, WITH SOFTUPDATES)
:     1497.09 real      1397.98 user       612.06 sys
:     1500.12 real      1399.33 user       609.79 sys
:     1494.82 real      1398.30 user       612.46 sys
:test1# cat x2		(SMP BUILD, STABLE, WITHOUT SOFTUPDATES)
:     2449.14 real      1401.34 user       625.54 sys
:     2389.75 real      1400.38 user       629.86 sys
:     2358.82 real      1403.26 user       624.93 sys
:
    ( ~889 second difference in real time)


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