Hi!
> so it appears that this lowlevel x86 performance bug(?) is more than 11
> years old! :-)
Probably 386's were not optimized for %fs==%gs==0 case?
BTW does it really make a difference for the CPU?
Pavel
> @@ -2803,9 +2803,10 @@
> load_TR(nr);
> load_LDT(&init_mm);
>
> - /*
> - * Clear all 6 debug registers:
> - */
> + /* Clear %fs and %gs. */
> + asm volatile ("xorl %eax, %eax; movl %eax, %fs; movl %eax, %gs");
> +
> + /* Clear all 6 debug registers: */
>
> #define CD(register) __asm__("movl %0,%%db" #register ::"r"(0) );
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This archive was generated by hypermail 2b29 : Thu Jan 31 2002 - 21:01:24 EST