Message ID | Pine.LNX.4.64.1008190933180.19440@hs20-bc2-1.build.redhat.com |
---|---|
State | Accepted |
Delegated to: | David Miller |
Headers | show |
From: Mikulas Patocka <mpatocka@redhat.com> Date: Thu, 19 Aug 2010 09:42:55 -0400 (EDT) >> #define BACKOFF_SETUP(reg) >> -#define BACKOFF_SPIN(reg, tmp, label) \ >> - ba,pt %xcc, label; \ >> - nop; > > I'm just curious, is there some good reason to place nop in the delay slot > instead of the anul bit? --- i.e. some inefficiency or bugs? It's definitely slower on pre-Niagara cpus. > BTW, I found a missing delay slot. Good catch, I'll apply this, thanks! -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Index: linux-2.6.35-preempt/arch/sparc/include/asm/system_64.h =================================================================== --- linux-2.6.35-preempt.orig/arch/sparc/include/asm/system_64.h 2010-08-19 15:35:45.000000000 +0200 +++ linux-2.6.35-preempt/arch/sparc/include/asm/system_64.h 2010-08-19 15:38:21.000000000 +0200 @@ -106,6 +106,7 @@ do { __asm__ __volatile__("ba,pt %%xcc, */ #define write_pic(__p) \ __asm__ __volatile__("ba,pt %%xcc, 99f\n\t" \ + " nop\n\t" \ ".align 64\n" \ "99:wr %0, 0x0, %%pic\n\t" \ "rd %%pic, %%g0" : : "r" (__p))