[PATCH] Optimization to avoid scanning all .pc files

[Marco Diego Aurélio Mesquita]

Hi Devs!

I tried to improve the patch a bit more. The "locations" hashtable is
now gone. Run times for the tests seem about 10% faster now.

Matthew would you mind to test it?

Also, I think the "path_positions" hashtable can be removed. Maybe it
will improve the speed a little bit more.


On Fri, Sep 9, 2016 at 6:08 PM, Matthew Hanna (BLOOMBERG/ 731 LEX)
<mhanna21 at bloomberg.net> wrote:
> Results of tests of this patch on our system are mixed. The optimization
> does
> not appear to be needed on our Linux boxes. The time to read our pkgconfig
> directory is in the milliseconds. On other platforms, the time is in
> seconds,
> so I was hopeful that this patch would reduce that time. It certainly
> reduces
> the minimum speed, but the maximum speed is actually increased. In one test,
> the time without the patch is 2 seconds, with almost all of that time taken
> up
> by the directory reading. With the patch, the minimum time is now in
> milliseconds for a low level library with few dependencies, but is now over
> 5
> seconds for a higher level library.
>
> From: marcodiegomesquita at gmail.com At: 08/27/16 10:53:48
> To: Matthew Hanna (BLOOMBERG/ 731 LEX), nicholson at endlessm.com
> Cc: pkg-config at lists.freedesktop.org
> Subject: Re: [PATCH] Optimization to avoid scanning all .pc files
>
> Hi Devs!
>
>
> Attached is just a small improvement to the patch: code improvements
> and path_position calculation is smarter. I think it is now good to
> go.
>
> Please review it.
>
>
> On Fri, Aug 26, 2016 at 10:04 PM, Marco Diego Aurélio Mesquita
> <marcodiegomesquita at gmail.com> wrote:
>> Hi Matthew!
>>
>> Thanks for the review. The attached patch implements the changes you
>> asked.
>>
>> Is there anything else that should be changed?
>>
>> On Fri, Aug 26, 2016 at 8:25 PM, Matthew Hanna (BLOOMBERG/ 731 LEX)
>> <mhanna21 at bloomberg.net> wrote:
>>> --- Original Sender: INTERNET2 .PROG/MSG/INT, BLOOMBERG/ 330 WEST ---
>>>
>>> The call to 'access' should be replaced by 'g_file_test' for portability
>>> and/or platform optimization.
>>>
>>> Are there whitespace changes in the diff? If so, please remove. It makes
>>> the diff very hard to read.
>>>
>>> ---
>>> Sent from Bloomberg Professional for Android
>>>
>>>
>>> ----- Original Message -----
>>> FROM: Marco Diego Aurélio Mesquita <marcodiegomesquita at gmail.com>
>>> At: 27-Aug-2016 01:03:59
>>>
>>> Hi devs!
>>>
>>> The attached patch improves pkg-config so that it will look for
>>> required .pc files only, instead of loading and parsing all known .pc
>>> files.
>>>
>>> Please review it.
>>>
>>> ----------------------------
>>>
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>
>
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