Re: [PATCH] Add minimal support for software performance countersfor ia64

[Peter Zijlstra]

On Wed, 2009-08-19 at 12:04 -0400, William Cohen wrote:
> +#ifdef __ia64__
> +#include "../../arch/ia64/include/asm/unistd.h"
> +#define rmb()          asm volatile("" ::: "memory")
> +#define cpu_relax()    asm volatile("" ::: "memory");
> +#endif

Surely the itanic has a real memory barrier? The kernel seems to use
something along the lines of mf.

Also, cpu_relax() seems to end up being asm volatile("hint @pause" :::
"memory"), although we don't seem to have an actual user of cpu_relax()
in perf atm.



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/