making the mac startup faster...

John.Maloney at disney.com John.Maloney at disney.com
Wed Jan 2 14:24:56 UTC 2002


John,

These timings loop pretty good. The file read time seems consistent
with other bulk-read operations I've timed. I believe file reading is
about 5-6 MB/sec on a Powerbook.

I'm not sure mapping the file will be faster, although I think  that's what
windows does, since we have to scan the heap to fixup the image, so
we probably have to page in most of the heap anyhow.

What's happening during the 1250 msecs between fixing up the image
and the first update screen event? I imagine that this time is spent
running Squeak startup code, which includes allocating the Display
bitmap, opening the sources files, etc. With a bit of cleverness, we
could probably use MessageTally to profile this code.

Good work cutting the I/O ops almost in half!

	-- John


>I've been looking into this. I've noticed on windows why when you 
>startup Squeak it just snaps up! But it takes seconds on the mac, why?
>
>Thanks to some OS-X tools, let alone the usage of fs_usage I've noted 
>that 3.2.1B5 does 1,574 I/O operations in order to startup. By apply 
>some thought to how plugins are looked for I've cut that to 902 I/Os
>
>Right now I get timings of
>11ms to start main to the point of image reading
>1,852ms to read a 15,1903,04 file, 7.8MB sec?
>386ms to fixup image.
>1,250ms to first update screen event in the interpreter.
>
>I'm considering mmap and other interesting things to perhaps speedup 
>the read, along with more review of how the directory lookup logic 
>and directory entries logic works. (Somewhat ugly due to the 
>transition to os-x).
>
>
>Let alone how the startup code hunts for the changes and source file, 
>and why we need to tap the nonexistent applescript plugin at startup 
>time.
>
>So I'm wondering if there are some suggestions out there.






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