[OT] Three Optimization Tips for C++

2012-12-19 Thread Andrei Alexandrescu

Vote up!

http://www.reddit.com/r/programming/comments/155ivw/three_optimization_tips_for_c_video/


Andrei


Re: [OT] Three Optimization Tips for C++

2012-12-20 Thread Joshua Niehus
On Thursday, 20 December 2012 at 05:29:46 UTC, Andrei 
Alexandrescu wrote:

Vote up!


http://www.reddit.com/r/programming/comments/155ivw/three_optimization_tips_for_c_video/

Andrei


Almost 2 years ago, I stumbled across your book at a Barnes&Nobel 
and began my journey with D. It turns out its an "unsigned" copy. 
 Any chance you'll sign it at the DConf?


Re: [OT] Three Optimization Tips for C++

2012-12-21 Thread bearophile

Andrei Alexandrescu:


http://www.reddit.com/r/programming/comments/155ivw/three_optimization_tips_for_c_video/


I appreciate such slides and videos, thank you for sharing. But 
If possible I'd like a link to the slides in a place where I 
don't have to register to download them.


I have also just seen this other slides pack from Jordan DeLong, 
it is very interesting, it's about a topic that is usually 
regarded as one of the strongest points of functional languages 
(that is using types to "make illegal states unrepresentable"):


http://www.reddit.com/r/cpp/comments/1571m9/facebook_nyc_tech_talk_jordan_delong_using/

Bye,
bearophile


Re: [OT] Three Optimization Tips for C++

2012-12-21 Thread Peter Alexander
On Thursday, 20 December 2012 at 05:29:46 UTC, Andrei 
Alexandrescu wrote:

Vote up!

http://www.reddit.com/r/programming/comments/155ivw/three_optimization_tips_for_c_video/


Andrei


I think the most interesting thing from that talk is when you 
said that Facebook's back end code is spending 15% of its time 
converting ints to strings.


I know you are looking at these small functions as simple 
examples of the optimisation tips you are giving, but I hope this 
isn't the kinds of optimisations you are doing at the Facebook. 
The problem isn't that the conversion is slow, the problem is 
that you are converting at all. Don't use text based formats for 
performance sensitive data!


Of course, maybe the 15% claim was pure exaggeration. I really 
hope that's the case.


Re: [OT] Three Optimization Tips for C++

2012-12-21 Thread Max Samukha
On Thursday, 20 December 2012 at 05:29:46 UTC, Andrei 
Alexandrescu wrote:

Vote up!

http://www.reddit.com/r/programming/comments/155ivw/three_optimization_tips_for_c_video/


Andrei


Nice talk. For anybody interested, PIC was made a bit faster by 
x64 due to introduction of RIP-relative addressing. Here is a 
concise and well-written article describing an x64 PIC 
implementation 
http://eli.thegreenplace.net/2011/11/11/position-independent-code-pic-in-shared-libraries-on-x64/.


Re: [OT] Three Optimization Tips for C++

2012-12-21 Thread Andrei Alexandrescu

On 12/21/12 7:23 AM, Peter Alexander wrote:

On Thursday, 20 December 2012 at 05:29:46 UTC, Andrei Alexandrescu wrote:

Vote up!

http://www.reddit.com/r/programming/comments/155ivw/three_optimization_tips_for_c_video/



Andrei


I think the most interesting thing from that talk is when you said that
Facebook's back end code is spending 15% of its time converting ints to
strings.


Not all back end code. Certain applications.


I know you are looking at these small functions as simple examples of
the optimisation tips you are giving, but I hope this isn't the kinds of
optimisations you are doing at the Facebook. The problem isn't that the
conversion is slow, the problem is that you are converting at all. Don't
use text based formats for performance sensitive data!

Of course, maybe the 15% claim was pure exaggeration. I really hope
that's the case.


Text representation has its own advantages.


Andrei


Re: [OT] Three Optimization Tips for C++

2012-12-24 Thread Tove
On Friday, 21 December 2012 at 16:28:35 UTC, Andrei Alexandrescu 
wrote:

use text based formats for performance sensitive data!

Of course, maybe the 15% claim was pure exaggeration. I really 
hope

that's the case.


Text representation has its own advantages.


Andrei


interesting, does it have to be base 10? would it not be feasible 
to use hex strings in some scenarios? possible with bswap, or 
bitscan etc?