Re: Regarding performance issues with the Emacs 25.1 Windows-build

[Phillip Lord]

Eli Zaretskii <address@hidden> writes:

>> From: Noam Postavsky <address@hidden>
>> Date: Wed, 9 Nov 2016 11:55:04 -0500
>> Cc: address@hidden, Emacs developers <address@hidden>
>> 
>> I think the problem is that the 25.1 build is not optimized: I did M-x
>> report-emacs-bug in each, notice that 25.1 has a setting for CFLAGS
>> which doesn't include -O2, while 24.5 doesn't have one (and hence uses
>> the default, which I believe does include -O2).
>> 
>> In GNU Emacs 25.1.1 (x86_64-w64-mingw32)
>>  of 2016-09-17 built on LAPHROAIG
>> Configured using:
>>  'configure --without-dbus --without-compress-install CFLAGS=-static'
>> 
>> In GNU Emacs 24.5.1 (i686-pc-mingw32)
>>  of 2015-04-11 on LEG570
>> Windowing system distributor `Microsoft Corp.', version 6.3.9600
>> Configured using:
>>  `configure --prefix=/c/usr --host=i686-pc-mingw32'
>
> That could indeed be the culprit: omitting -O2 makes Emacs 2 to 3
> times slower, IME.
>
> Phillip, could you please double-check the value of CFLAGS in the
> Makefiles in your build tree?  Does it include any optimization
> options?

I don't have the make files to hand, but I do have the commands that I
used, and yes, I did set CFLAGS=-static. IIRC, we had a long discussion
about this, and it was to avoid a dependency on libwinpthread. It didn't
occur to me that setting CFLAGS would effect other defaults.

I'll try and build with "-O2" added and check tonight.

Phil