I've just read the article over at Dr Dobbs by Walter

http://www.drdobbs.com/cpp/increasing-compiler-speed-by-over-75/240158941

and this line caught my eye:

> Even if you know your code well, you're likely wrong about where
> the performance bottlenecks are. Use a profiler. If you haven't
> used one on your codebase in a while, it's highly likely there's
> a bottleneck in there that's fixable with just a few lines of code.

What profilers do you use with D especially for Linux and Mac? I've been compiling with -profile and trying to grok the output.

On Thu, Jul 25, 2013 at 08:15:42PM +0200, Gary Willoughby wrote:
> I've just read the article over at Dr Dobbs by Walter
> 
> http://www.drdobbs.com/cpp/increasing-compiler-speed-by-over-75/240158941
> 
> and this line caught my eye:
> 
> >Even if you know your code well, you're likely wrong about where the performance bottlenecks are. Use a profiler. If you haven't used one on your codebase in a while, it's highly likely there's a bottleneck in there that's fixable with just a few lines of code.

I can personally testify to the truth of this statement. All too often, too much time is spent "optimizing" parts of code that are actually irrelevant to the performance of the program, because the bottleneck lies elsewhere, often in an unexpected place. (Not to mention that such premature optimization makes your code harder to write, harder to read, harder to maintain, and therefore more prone to bugs.)

I remember at least one instance in which a profiler immediately revealed an fprintf (this was C/C++ code, back in the day) where it shouldn't be, the removal of which instantly improved performance by at least 30%, probably more.


> What profilers do you use with D especially for Linux and Mac? I've been compiling with -profile and trying to grok the output.

I use gdc with gprof, usually. I've only tried dmd -profile a few times.


T

-- 
I think Debian's doing something wrong, `apt-get install pesticide', doesn't seem to remove the bugs on my system! -- Mike Dresser

25-Jul-2013 22:15, Gary Willoughby пишет:
> I've just read the article over at Dr Dobbs by Walter
>
> http://www.drdobbs.com/cpp/increasing-compiler-speed-by-over-75/240158941
>
> and this line caught my eye:
>
>> Even if you know your code well, you're likely wrong about where
>> the performance bottlenecks are. Use a profiler. If you haven't
>> used one on your codebase in a while, it's highly likely there's
>> a bottleneck in there that's fixable with just a few lines of code.
>
> What profilers do you use with D especially for Linux and Mac? I've been
> compiling with -profile and trying to grok the output.

I've found
valgrind --tool=callgrind
+ kcachegrind
to be quite awesome.

Other options are the usual profilers of your OS/CPU vendor:
perf, AMD CodeAnalyst, Intel VTune

-- 
Dmitry Olshansky