Crafty suprise

[jwes]

I was using crafty to analyze games at a fixed depth of 7 on my Core 2 duo on 64 bit Windows 7 and discovered it was 10 times faster to use only 1 thread.

[bob]

I was using crafty to analyze games at a fixed depth of 7 on my Core 2 duo on 64 bit Windows 7 and discovered it was 10 times faster to use only 1 thread.

That's a tough test. It is effectively "ponder=off" so that each search requires creating new threads, which is significantly more effort than just doing the 7 ply search on one processor. In a real game, it will be faster with more threads, because the threads never exit unless you use ponder=off and the default smpnice=1.

Really is not a surprise to me at all... That's why I added smpnice so recently, it is a bad idea for most kinds of tests, unless you run two programs on one computer where spinning threads from one will interfere with the other...