Re: Task dispatching
Re: Task dispatching
- Subject: Re: Task dispatching
- From: Jon Sigman <email@hidden>
- Date: Tue, 13 Sep 2011 15:03:32 -0700 (PDT)
You're right -- I ran a new test with a different 1GB matrix file, and the first time that it is mmap'd it takes approx 30 seconds; afterwards < 1 second to map to (and loop through) what I suppose is an already cached image. I did verify that the data is there (it's a read-only dense matrix). Still, this should work out, since after the initial mmap load, it's quite speedy.
________________________________
From: Scott Ribe <email@hidden>
To: Steve Sisak <email@hidden>
Cc: Jon Sigman <email@hidden>; list-cocoa-dev <email@hidden>
Sent: Tuesday, September 13, 2011 2:55 PM
Subject: Re: Task dispatching
On Sep 13, 2011, at 3:28 PM, Steve Sisak wrote:
> Actually, I believe that mmap just maps the the file into memory using the VM system -- it's initially paged out and read in as each page is touched...
Yes, thus my comment. Did the OP actually read all values? The time seems too fast for that unless everything was cached. But on the other hand the time seemed way too slow to just be the mmap call itself without actually reading data.
--
Scott Ribe
email@hidden
http://www.elevated-dev.com/
(303) 722-0567 voice
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