Thread (4 messages) 4 messages, 3 authors, 2001-01-16

Re: mmap()/VM problems in 2.4.0

From: Mike Galbraith <hidden>
Date: 2001-01-15 20:49:59
Also in: lkml

On 15 Jan 2001, Zlatko Calusic wrote:
"Vlad Bolkhovitine" [off-list ref] writes:
quoted
Here is updated info for 2.4.1pre3:

Size is MB, BlkSz is Bytes, Read, Write, and Seeks are MB/sec

with mmap()

 File   Block  Num          Seq Read    Rand Read   Seq Write  Rand Write
 Dir    Size   Size    Thr Rate (CPU%) Rate (CPU%) Rate (CPU%) Rate (CPU%)
------- ------ ------- --- ----------- ----------- ----------- -----------
   .     1024   4096    2  1.089 1.24% 0.235 0.45% 1.118 4.11% 0.616 1.41%

without mmap()
   
 File   Block  Num          Seq Read    Rand Read   Seq Write  Rand Write
 Dir    Size   Size    Thr Rate (CPU%) Rate (CPU%) Rate (CPU%) Rate (CPU%)
------- ------ ------- --- ----------- ----------- ----------- -----------
   .     1024   4096    2  28.41 41.0% 0.547 1.15% 13.16 16.1% 0.652 1.46%


Mmap() performance dropped dramatically down to almost unusable level. Plus,
system was unusable during test: "vmstat 1" updated results every 1-2 _MINUTES_!
You need Marcelo's patch. Please apply and retest.
My box thinks quite highly of that patch fwiw, but insists that he needs
to apply Jens Axboes' blk patch first ;-)  (Not because of tiobench)

	-Mike

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