Re: [INTERNALS-WIN] [PATCH] Microsecond resolution and accuracy on Windows

Hi Stas,

----- Original Message -----
From: "Stas Malyshev"
Sent: Monday, September 01, 2014

> Hi!
>
>> It's much more optimized than what's there now, and slightly over the old
>> implementation.  Not sure if I should give the saved patch link, or the
>> "live compare" (?) on Github, so I'll do both for now:
>> http://realplain.com/php/microtime_5_4.diff
>> https://github.com/matt-moo/php-src/compare/PHP-5.4.diff
>>
>> Against 5.4 since that's what I quickly worked on so it's ready for the 
>> next
>> 5.4 release (Stas?). (Although I guess we're supposed to change the 
>> oldest
>> branch usually?)
>
> Looking at the patch, it looks like unfortunately it changes a global
> structure (_php_win32_core_globals) which breaks binary compatibility. I
> think if you move the additional value to the end of the structure it
> should be ok though, since other offsets should not change then.

I was wondering about that myself (back when it was changed last, March 
2013) when a few members were removed from that structure, so I figured it 
was OK to put one back. :-)  No problem with binary compatibility then...?

http://git.php.net/?p=php-src.git;a=commitdiff;h=b903d2d6cdf9a9efac181a21e95ea93dc8a864dd#patch5

> I'm also not sure how important it is how have it for 5.4. Does the
> problem that this patch fixes exist only in older versions of Windows or
> on all versions? What are the actual effects of this problem - is it
> just lower resolution of microtime or there can be something seriously
> wrong with the whole result? If it's just lower resolution, I'd prefer
> this to go into 5.5 as the change is pretty extensive.

I don't think the change is that extensive (maybe if you're comparing to 
current version ;-)).  As I said in my first "5.4 - last call" reply, it's 
similar to the previous old version.  You can see what was removed from 
time.c last March in the above diff...  My changes are like a simplified 
version of that (there for over a decade), restored, but without the 
possibility of "seriously wrong results" (not an issue now either, but we've 
also had very low resolution).

The issues, and these changes, don't affect Windows 8/Server 2012 and later 
(they have a high-res time function like *nix gettimeofday()).  So Win 7 and 
before.  See referenced bugs: #64633, #65626 (uniqid())


Thanks,
Matt