64 bit compiling help

[Edsel Apostol]

I have managed to compile my engine in 64 bit. I don't have a 64 bit system to test it so I have a couple of questions to the experts on this matter.

My engine is bitboard based and my tester noticed a speed increase of only 37% compared to the 32 bit version. Is this speed-up normal? His machine is an Athlon X2 3600+ running XP 64 bit.

I'm also not sure about this:

Code: Select all

#if defined(_WIN64) || defined(_LP64)
    #define VERSION64BIT
#endif

#if defined(VERSION64BIT)
// 64 bit code here
#else
// 32 bit code here
#endif

I'm using the macro VERSION64BIT to separate my 32 bit specific to 64 bit specific code. Is this implementation correct?

And lastly:

Code: Select all

typedef unsigned long long u64;
typedef unsigned int u32;
typedef unsigned short u16;
typedef unsigned char u8;
typedef signed long long s64;
typedef signed int s32;
typedef signed short s16;
typedef signed char s8;

Is the code above correct? Or I need to revise it for the 64 bit compile? The compile seems to work with that code above.

[brianr]

The 64-bit speed-up varies quite a bit based on the engine.
Crafty gains about 50%, IIRC.
Tinker, which is bitboard, but less so than Crafty, only about 25%.
Your results seem to be well within an expected range.

Has anyone seen greater than a 50% increase?

[beachknight]

Hi Edsel,

I'd be interested including both versions
of new TL beta in my tourneys. So I'll wait
for your notice for a download on your
website.

best,

[Edsel Apostol]

I think there are engines that has a speed-up of more than 50% but I couldn't remember the results posted here before. Maybe Glaurung and Rybka does.

[Edsel Apostol]

I will try to finish the tests first on the settings and I will try to add Chess 960 support before I will release a new version. If you want, just send me an e-mail and I will send you the latest beta including the 64 bit version.

[Aleks Peshkov]

It is impossible to predict how much source code is portable without testing.
After reading Agner's optimization guids, that is what I use:

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#if !defined PLATFORM_BASE
    #if defined __x86_64__ || defined _M_X64
        #define USE_ASM
        #define PLATFORM_BASE 64
    #elif defined __i386__ || defined _M_IX86 || defined __INTEL__
        #define USE_ASM
        #define PLATFORM_BASE 32
    #elif defined __IA64__ || _WIN64 || __LP64__
        #define PLATFORM_BASE 64
    #else
        #define PLATFORM_BASE 32
    #endif
#endif

[Edsel Apostol]

It seems to cover everything. Can I use this code in my engine?

Code: Select all

#if !defined PLATFORM_BASE
    #if defined __x86_64__ || defined _M_X64
        #define USE_ASM
        #define PLATFORM_BASE 64
    #elif defined __i386__ || defined _M_IX86 || defined __INTEL__
        #define USE_ASM
        #define PLATFORM_BASE 32
    #elif defined __IA64__ || _WIN64 || __LP64__
        #define PLATFORM_BASE 64
    #else
        #define PLATFORM_BASE 32
    #endif
#endif

[Bo Persson]

I think there are engines that has a speed-up of more than 50% but I couldn't remember the results posted here before. Maybe Glaurung and Rybka does.

I think you should be rather satisfied with a 37% speedup from a simple recompile!

If you do some tuning for the 64 bit version, I am sure you can also reach 50% and beyond. Some things that a relatively expensive in 32 bit mode are now cheaper, and can be used in 64 bit mode. That would affect your nps, if you try it out.

[Edsel Apostol]

Thanks Bo. I'm just asking for other engine performance to have something to compare my engine's 64 bit speed-up.

I may be a little disappointed as I expect something more than 50%. Maybe my 32 bit version is optimized already.