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Re: New stat stuff (was [PATCH] improve performance of stat() ope rations (e.g. ls -lR ))
- From: Christopher Faylor <cgf at redhat dot com>
- To: cygwin-patches at cygwin dot com
- Date: Wed, 29 May 2002 20:36:45 -0400
- Subject: Re: New stat stuff (was [PATCH] improve performance of stat() ope rations (e.g. ls -lR ))
- References: <FE045D4D9F7AED4CBFF1B3B813C853376762CA@mail.sandvine.com>
- Reply-to: cygwin-patches at cygwin dot com
On Wed, May 29, 2002 at 08:30:09PM -0400, Don Bowman wrote:
>
>> On Tue, May 28, 2002 at 10:25:37PM -0400, Christopher Faylor wrote:
>> >On Tue, May 28, 2002 at 09:58:52PM -0400, Don Bowman wrote:
>> >>
>> >>So I've performed a mini-benchmark of Chris' changes.
>> >>
>> >>I did a ls -lR >/dev/null of the cygwin source tree on my
>> >>notebook.
>> >>
>> >>Baseline (current setup.exe install): 1m14.9s
>> >>'statquery' patch I sent earlier: 4.081s
>> >>Current CVS tree: 3.718s
>> >>Current CVS tree w/ -E switch to mount: 3.711s
>> >>Current CVS tree w/ -X switch to mount: 3.716s
>> >>
>> >>Not all that scientific, I ran each twice, took the 2nd timing.
>> >>So, looks good, excellent work. I still don't see any
>> >>difference on the -E or the -X tho'.
>> >
>> >That has got to mean that there's something wrong in the stat
>> >logic. I didn't do anything to speed up the normal case, AFAIK,
>> >unless you're doing this on a FAT/FAT32 partition.
>>
>> Actually, even in that case, it shouldn't make that big a deal.
>
>Its the anti-virus. Your change no longer opens the file for read,
>so the anti-virus doesn't do anything, thus the enormous difference.
>As to why the negligible difference between -E/-X/nothing, no
>idea.
No, my change should not have stopped the file from being opened
in the normal case. It was only in the -E, -X cases that it should
have an effect.
I did have a logic error which is corrected in the latest snapshot.
cgf