[Patch] Regex bracket matcher cache optimization

Tim Shen timshen91@gmail.com
Wed Jan 8 22:11:00 GMT 2014


On Wed, Jan 8, 2014 at 5:20 AM, Paolo Carlini <paolo.carlini@oracle.com> wrote:
> On 01/08/2014 10:24 AM, Jonathan Wakely wrote:
>> Ouch! Yes, that's quite a bit slower, and this code is already very
>> slow to compile.

With this patch (who is based on a-fixed.diff, committed earlerly),
who use templated member functions instead of templating the whole
_Compiler, time consumption is:
g++ -g -Wall -std=c++11 -g -Wall -std=c++11 -O3 regextest.cc  3.79s
user 0.14s system 98% cpu 3.981 total

Comparing to 4.5s it's better and probably fine.

Booted and tested with -m32 and -m64 respectively.

> I only want to add that, besides keeping compile-time under control for
> 4.9.0 - please investigate a bit more along the mentioned lines - we should
> also start experimenting with exporting the instantiations. I don't know
> what the other implementations are doing, but in general it definitely makes
> sense, for compile-time performance too. I think we already said that some
> time ago, but the issue seems more important now. Maybe it's really
> unavoidable if we need template complexity for first class run-time
> performance.

After this patch I plan to instantiate _Compiler and _Executor.


-- 
Regards,
Tim Shen



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