[systemd-devel] [PATCH] use dolt.m4 to speedup compilation

[Harald Hoyer]

On 06.03.2015 01:58, josh at joshtriplett.org wrote:
> On Fri, Mar 06, 2015 at 12:55:38AM +0100, Michael Biebl wrote:
>> 2015-03-05 11:58 GMT+01:00  <harald at redhat.com>:
>>> From: Harald Hoyer <harald at redhat.com>
>>>
>>> The speedup is significant
>>>
>>> Original libtool
>>> $ ccache -C && make clean && time make -j4
>>> […]
>>> real    6m4.104s
>>> user    13m49.234s
>>> sys    7m37.864s
>>>
>>> Original libtool + dolt
>>> $ ccache -C && make clean && time make -j4
>>> […]
>>> real    2m24.869s
>>> user    7m30.198s
>>> sys    1m17.813s
>>
>> Hm, the speedup is nowhere near as significant here:
>> without dolt (make):
>> real 4m2.749s
>> user 3m9.304s
>> sys 0m19.032s
>>
>> with dolt (make):
>> real 3m33.756s
>> user 2m59.476s
>> sys 0m17.632s
>>
>> without dolt (make -j6):
>> real 1m42.001s
>> user 5m3.680s
>> sys 0m26.608s
>>
>> with dolt (make -j6)
>> real 1m35.267s
>> user 4m50.956s
>> sys 0m24.724s
>>
>>
>> libtool version is 2.4.2.
> 
> That's more what I'd expect with current versions of libtool, which has
> supposedly fixed many of the issues that motivated the creation of dolt
> in the first place.

See
<https://harald.hoyer.xyz/2015/03/05/libtool-getting-rid-of-180000-sed-forks/>
to find out about the culprit and a libtool fix.