From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3x5n7k38ktzDqTy for ; Tue, 11 Jul 2017 00:06:25 +1000 (AEST) Subject: Re: [PATCH v6 1/7] perf/core: Define the common branch type classification To: Peter Zijlstra , Segher Boessenkool Cc: Michael Ellerman , acme@kernel.org, jolsa@kernel.org, mingo@redhat.com, alexander.shishkin@linux.intel.com, kan.liang@intel.com, ak@linux.intel.com, linuxppc-dev@lists.ozlabs.org, Linux-kernel@vger.kernel.org, yao.jin@intel.com References: <1492690075-17243-1-git-send-email-yao.jin@linux.intel.com> <1492690075-17243-2-git-send-email-yao.jin@linux.intel.com> <87r2xoj08g.fsf@concordia.ellerman.id.au> <820424b8-d7b3-56cc-2b97-ec570d44ec25@linux.intel.com> <87h8ykvayi.fsf@concordia.ellerman.id.au> <20170710131049.GA13471@gate.crashing.org> <20170710134658.k44bpa7tra2woyiu@hirez.programming.kicks-ass.net> From: "Jin, Yao" Message-ID: Date: Mon, 10 Jul 2017 22:06:21 +0800 MIME-Version: 1.0 In-Reply-To: <20170710134658.k44bpa7tra2woyiu@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8; format=flowed List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 7/10/2017 9:46 PM, Peter Zijlstra wrote: > On Mon, Jul 10, 2017 at 08:10:50AM -0500, Segher Boessenkool wrote: > >>> PERF_BR_INT is triggered by instruction "int" . >>> PERF_BR_IRQ is triggered by interrupts, traps, faults (the ring 0,3 >>> transition). >> So your "PERF_BR_INT" is a system call? > The "INT" thing has indeed been used as system call mechanism (typically > INT 80). But these days we have special purpose syscall instructions. > > It could maybe be compared to the PPC "Unconditional TRAP with > immediate" where you use the immediate value as an index into a handler > vector. > >> And PERF_BR_IRQ is not an interrupt request (as its name suggests), >> not what we call an "external interrupt" either; instead it is every >> interrupt that is not a system call? > It is actual interrupts, but also faults, traps and all the other > exceptions not caused by "INT" I think. > Yes. It's interrupt, traps, faults. If from is in the user space and to is in the kernel, it indicates the ring3 -> ring0 transition. If the from instruction is not syscall or other ring transition instruction, it should be interrupt, traps and faults. That's how we get the PERF_BR_IRQ on x86. Anyway, maybe we just use a minimum but the most common set of branch types now, it could be a good start and acceptable on all architectures. PERF_BR_COND = 1, /* conditional */ PERF_BR_UNCOND = 2, /* unconditional */ PERF_BR_IND = 3, /* indirect */ PERF_BR_CALL = 4, /* call */ PERF_BR_IND_CALL = 5, /* indirect call */ PERF_BR_RET = 6, /* return */ Thanks Jin Yao