From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752283AbdGMOb5 (ORCPT ); Thu, 13 Jul 2017 10:31:57 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:58207 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751200AbdGMOb4 (ORCPT ); Thu, 13 Jul 2017 10:31:56 -0400 Date: Thu, 13 Jul 2017 16:31:50 +0200 From: Peter Zijlstra To: Jin Yao Cc: acme@kernel.org, jolsa@kernel.org, mingo@redhat.com, alexander.shishkin@linux.intel.com, mpe@ellerman.id.au, Linux-kernel@vger.kernel.org, ak@linux.intel.com, kan.liang@intel.com, yao.jin@intel.com Subject: Re: [PATCH v8 2/7] perf/x86/intel: Record branch type Message-ID: <20170713143150.ceby42dokdeagxas@hirez.programming.kicks-ass.net> References: <1499947459-4527-1-git-send-email-yao.jin@linux.intel.com> <1499947459-4527-3-git-send-email-yao.jin@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1499947459-4527-3-git-send-email-yao.jin@linux.intel.com> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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; > +}