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Date:      Sun, 7 Feb 1999 00:39:28 -0800 (PST)
From:      Matthew Dillon <dillon@apollo.backplane.com>
To:        "John S. Dyson" <dyson@iquest.net>
Cc:        current@FreeBSD.ORG
Subject:   Re: Significant page coloring improvement
Message-ID:  <199902070839.AAA20087@apollo.backplane.com>
References:   <199902070615.BAA00269@y.dyson.net>

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    Ah, interesting.  I understand the second bit.  The first bit seems
    somewhat odd, though - the automatic page coloring adjustment made
    by _vm_object_allocate() doesn't work well enough for kmem_object?

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>

:When reviewing the VM code regarding another issue (another significant
:VM contributor had found an interesting anomoly), I noticed that the
:coloring wasn't as complete as it should be.
:
:Attached is a patch that appears to make a reasonable improvement in
:performance, when using both my slightly more advanced VM kernel, and
:also the stuff in -current.  I seem to see a fork() only performance
:improvement of about 10% on a 2 processor SMP PPro, using lmbench.  On
:vfork (which isn't completely implemented on a PPro, but is still faster
:than fork), the improvement appears to be about 5%.
:
:Of course, any page coloring improvement is dependent on alot of factors,
:but the missing object coloring handling is a problem...
:
:-- 
:John                  | Never try to teach a pig to sing,
:dyson@iquest.net      | it makes one look stupid
:jdyson@nc.com         | and it irritates the pig.
:
:...
:Index: vm/vm_object.c
:===================================================================
:RCS file: /local/home/ncvs/src/sys/vm/vm_object.c,v
:retrieving revision 1.144
:diff -r1.144 vm_object.c
:215a216
:> 	kmem_object->pg_color = (kernel_object->pg_color + PQ_L2_SIZE/4) & PQ_L2_MASK;
:945a947
:> 		result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & PQ_L2_MASK;
:
:--ELM918368107-256-0_--
:
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