Messages in this thread | | | Date | Thu, 13 Jul 2017 16:31:50 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v8 2/7] perf/x86/intel: Record branch type |
| |
On Thu, Jul 13, 2017 at 08:04:14PM +0800, Jin Yao wrote: > +#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_UNKNOWN, /* X86_BR_INT */ > + PERF_BR_UNKNOWN, /* X86_BR_IRET */ > + PERF_BR_COND, /* X86_BR_JCC */ > + PERF_BR_UNCOND, /* X86_BR_JMP */ > + PERF_BR_UNKNOWN, /* X86_BR_IRQ */ > + PERF_BR_IND_CALL, /* X86_BR_IND_CALL */ > + PERF_BR_UNKNOWN, /* X86_BR_ABORT */ > + PERF_BR_UNKNOWN, /* X86_BR_IN_TX */ > + PERF_BR_UNKNOWN, /* X86_BR_NO_TX */ > + PERF_BR_CALL, /* X86_BR_ZERO_CALL */ > + PERF_BR_UNKNOWN, /* X86_BR_CALL_STACK */ > + PERF_BR_IND, /* X86_BR_IND_JMP */ > + }; > + > + type >>= 2; /* skip X86_BR_USER and X86_BR_KERNEL */
> + mask = ~(~0 << 1);
OCC worthy means of writing: 1
> + > + for (i = 0; i < X86_BR_TYPE_MAP_MAX; i++) { > + if (type & mask) > + return branch_map[i]; > + > + type >>= 1; > + }
That is some of the more confused code I've seen in a while :/
if (type) return branch_map[__ffs(type)];
is what you meant to write, no?
> + > + return PERF_BR_UNKNOWN; > +}
| |