icc is a pretty garbage C++ compiler, unless you are doing exactly the type
of linear algebra operations that they optimise to death (on Intel
processors at least :) for benchmarketing.
On 23 November 2014 at 21:53, Thierry Dumont
wrote:
> Le 23/11/2014 20:53, Jeroen Demeyer a écrit :
>
>> On 20
Le 23/11/2014 20:53, Jeroen Demeyer a écrit :
On 2014-11-23 19:05, Thierry Dumont wrote:
Vtune shows, for example, that a call to std::copy is
not as fast as a for loop, which is turned by the compiler in a memcopy
(probably std::copy is not!).
If that's the case, get a better C++ compiler.
h
On 23 November 2014 at 20:41, Thierry Dumont
wrote:
> But what about the quick sort? is it sure that the implementation cannot
> degenerate? it is well known all the efficiency can be lost if the "key"
> used for partition is not chosen as it should be... What about replacing
> the quick sort by
On 2014-11-23 19:05, Thierry Dumont wrote:
Vtune shows, for example, that a call to std::copy is
not as fast as a for loop, which is turned by the compiler in a memcopy
(probably std::copy is not!).
If that's the case, get a better C++ compiler.
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Le 23/11/2014 19:09, Nathann Cohen a écrit :
Hello !
What about likwid https://code.google.com/p/likwid ? It is free. Did
somebody used it to measure cython code performances?
Never tried vtune, nor likwid.
What is the size of what you are sorting ? If it is small enough to fit in
the cache
Le 23/11/2014 19:07, Francesco Biscani a écrit :
On 23 November 2014 at 18:07, Volker Braun mailto:vbraun.n...@gmail.com>> wrote:
C++ std::sort will be able to inline the comparator.
Just look at the assembly code:-)
+1
std::sort() will do exactly what you describe, only in a type-safe
There's a sort.h library you should be able to include that will have quick
sort + many others, and will allow the compiler to properly inline
functions. https://github.com/swenson/sort (disclaimer: I wrote it). I get
about a 10x speed improvement over qsort just for the ability to inline
functions
On 23 November 2014 at 19:05, Thierry Dumont
wrote:
>
> Is gprof enough powerful with modern architectures on such programs? from
> my point of view, no.
> There are non free, commercial, tools like vtune which can do fantastic
> measurement job. Vtune shows, for example, that a call to std::copy
Hello !
> What about likwid https://code.google.com/p/likwid ? It is free. Did
> somebody used it to measure cython code performances?
Never tried vtune, nor likwid.
> What is the size of what you are sorting ? If it is small enough to fit in
> the caches, and better in the L1 cache, you can pos
On 23 November 2014 at 18:07, Volker Braun wrote:
>
> C++ std::sort will be able to inline the comparator.
>
+1
std::sort() will do exactly what you describe, only in a type-safe and
compiler-checked automatic way.
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Le 23/11/2014 18:07, Volker Braun a écrit :
Did you profile your code on the C-level? e.g. using gprof? As a rule of
thumb, guesses about where the bottleneck is are wrong :-) Its entirely
conceivable that branch prediction and speculative execution solve this
already for you.
Is gprof enough
Yo !
> Did you profile your code on the C-level? e.g. using gprof? As a rule of
> thumb, guesses about where the bottleneck is are wrong :-) Its entirely
> conceivable that branch prediction and speculative execution solve this
> already for you.
Yeees daddy :-P
I did that like a grown man w
Did you profile your code on the C-level? e.g. using gprof? As a rule of
thumb, guesses about where the bottleneck is are wrong :-) Its entirely
conceivable that branch prediction and speculative execution solve this
already for you.
C++ std::sort will be able to inline the comparator.
Link-t
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