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Re: Cygwin Performance and stat()


On Thu, Jun 03, 2010 at 05:32:46PM -0700, Christopher Wingert wrote:
>> On Thu, Jun 03, 2010 at 10:35:55AM -0700, Christopher Wingert wrote:
>>>Using strace I was able to look at some of the functions that are
>>>enumerated by debugging calls.
>>>
>>>The trace below is done by ls.exe for each file (approximately 95k files
>>> @
>>>88 mSecs/file), approximately 40 mSecs are spent in lstat64() and another
>>>47 mSecs are spent in getacl().
>>
>>You're undoubtedly misinterpreting the timestamps in strace.  They
>>don't indicate the amount of time spent in anything.  They are just
>>timestamps.
>
>Undoubtedly, no.
>
>I am doing basic subtraction based on the synchronous call made from
>the ls.exe executable to the cygwin1.dll and the timestamp provided by
>strace.

Yeah, that's what I thought you were doing.  Given that the timestamps
don't indicate "elapsed time of function X", it's not always possible to
figure out how long a function takes by subtracting.  Subtracting
timestamps shows the delta between one time that someone thought to put
an strace_printf in the code and another time that someone thought to
put an strace_printf in the code.  There is no guarantee that there is
an strace_printf at entry or exit of a function.

It is a shame that we weren't more standardized in our strace output so
that kind of thing could be possible.

>>You may be missing how this project is run.  The current maintainers of
>>everything read this mailing list.  You don't need to contact anyone
>>personally.  Actually, this is typical of many open source projects.
>
>Actually it is atypical for core developers to monitor a high volume
>generic question list such as this one, at least from my experience on
>other open source projects.  The core developers would leave it to some
>nay-saying lackey.

Well, for example, the core developers of gcc monitor the gcc mailing
list which can have higher traffic than this one.  Even the linux core
developers monitor the list for interesting threads.  Ditto freebsd
developers.  binutils developers monitor the binutils list.  gdb
developers monitor the gdb and gdb-patches mailing lists.  I'd be
surprised if there was a popular free software project with a high
volume mailing list where a core developer would be willing to have
private conversations with people who don't know the code base well.

However, for Cygwin, the web site says multiple times in multiple places
that you shouldn't send private email and to use the mailing list.  So,
other projects aside that really is how we do things here.

Oh, and it isn't clear if you're implying that I'm a lackey but I'm
really not.

cgf

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