On Thu, Apr 20, 2017 at 08:07:50PM +0800, Jin Yao wrote:
SNIP
>
> +#define X86_BR_TYPE_MAP_MAX 16
> +
> +static int
> +common_branch_type(int type)
> +{
> + int i, mask;
> + const int branch_map[X86_BR_TYPE_MAP_MAX] = {
> + PERF_BR_CALL, /* X86_BR_CALL */
> + PERF_BR_RET, /* X86_BR_RET */
> + PERF_BR_SYSCALL, /* X86_BR_SYSCALL */
> + PERF_BR_SYSRET, /* X86_BR_SYSRET */
> + PERF_BR_INT, /* X86_BR_INT */
> + PERF_BR_IRET, /* X86_BR_IRET */
> + PERF_BR_JCC, /* X86_BR_JCC */
> + PERF_BR_JMP, /* X86_BR_JMP */
> + PERF_BR_IRQ, /* X86_BR_IRQ */
> + PERF_BR_IND_CALL, /* X86_BR_IND_CALL */
> + PERF_BR_NONE, /* X86_BR_ABORT */
> + PERF_BR_NONE, /* X86_BR_IN_TX */
> + PERF_BR_NONE, /* X86_BR_NO_TX */
> + PERF_BR_CALL, /* X86_BR_ZERO_CALL */
> + PERF_BR_NONE, /* X86_BR_CALL_STACK */
> + PERF_BR_IND_JMP, /* X86_BR_IND_JMP */
> + };
> +
> + type >>= 2; /* skip X86_BR_USER and X86_BR_KERNEL */
> + mask = ~(~0 << 1);
is that a fancy way to get 1 into the mask? what do I miss?
> +
> + for (i = 0; i < X86_BR_TYPE_MAP_MAX; i++) {
> + if (type & mask)
> + return branch_map[i];
I wonder some bit search would be faster in here, but maybe not big deal
jirka
> +
> + type >>= 1;
> + }
> +
> + return PERF_BR_NONE;
> +}
> +
> /*
