World Draughts Forum

It is currently Mon Dec 17, 2018 19:45

All times are UTC+01:00




Post new topic  Reply to topic  [ 1 post ] 
Author Message
PostPosted: Tue Jun 19, 2018 18:10 
Offline

Joined: Sat Apr 28, 2007 14:53
Posts: 743
Real name: Ed Gilbert
Location: Morristown, NJ USA
After Joost Buijs wrote on another forum that the PEXT instruction is very slow on AMD processors, I decided to check it, as kingsrow uses PEXT in the indexing for the eval function. I check if PEXT is available and use it if it is. It normally gives about a 10% search speedup. If PEXT is not available, a software emulation is used that does a few shifts and AND/OR's.

Krzysztof has an AMD TR4 Ryzen Threadripper 1950x. He kindly ran an experiment for me and recorded these kingsrow search speeds:

- Using my software emulation of SHIFT/AND/OR's: 6712 KN/s
- Using the PEXT intrinsic: 3072 KN/s

PEXT is *really* slow on AMD! I will modify kingsrow to not use it on AMD.

-- Ed


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 1 post ] 

All times are UTC+01:00


Who is online

Users browsing this forum: No registered users and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Limited