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Date:      Tue, 2 Jul 2002 22:14:21 +1000 (EST)
From:      Bruce Evans <bde@zeta.org.au>
To:        Matthew Dillon <dillon@apollo.backplane.com>
Cc:        Julian Elischer <julian@elischer.org>, "Long, Scott" <Scott_Long@adaptec.com>, FreeBSD current users <current@FreeBSD.ORG>
Subject:   Re: -current results (was something funny with soft updates?)
Message-ID:  <20020702215851.A11958-100000@gamplex.bde.org>
In-Reply-To: <200207020314.g623Eke5038019@apollo.backplane.com>

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On Mon, 1 Jul 2002, Matthew Dillon wrote:

>     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.

>     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.

This seems like the right diagnosis.  The new gcc is very well pessimized.
A 60% increase in user times is normal :-(.  Your increase of almost 70%
seems a little high.  I guess this is because the user times are not quite
directly comparable.  SMP can easily increase user time by causing more
cache misses...

> :	(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)

Bruce


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