From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Clark Subject: Re: [RFC PATCH 2/3] perf tools: Add support for "report" for some spe events Date: Wed, 16 Oct 2019 10:12:43 +0000 Message-ID: <58bed363-41ee-e425-a36e-e3c69d1a4e90@arm.com> References: <1564738813-10944-1-git-send-email-tanxiaojun@huawei.com> <1564738813-10944-3-git-send-email-tanxiaojun@huawei.com> <0ac06995-273c-034d-52a3-921ea0337be2@arm.com> <016c1ce8-7220-75a2-43fa-0efe150f897c@huawei.com> <805660ca-1cf3-4c7f-3aa2-61fed59afa8b@arm.com> <637836d6-c884-1a55-7730-eeb45b590d39@huawei.com> <2b1fc8c7-c0b9-f4b9-a24f-444bc22129af@huawei.com> <335fedb8-128c-7d34-c5e8-15cd660fe12e@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <335fedb8-128c-7d34-c5e8-15cd660fe12e@huawei.com> Content-Language: en-US Content-ID: <6D50A32F91C7D94A9752A1E7B029CD57@eurprd08.prod.outlook.com> Sender: linux-kernel-owner@vger.kernel.org To: Tan Xiaojun , Jeremy Linton , "peterz@infradead.org" , "mingo@redhat.com" , "acme@kernel.org" , "alexander.shishkin@linux.intel.com" , "jolsa@redhat.com" , "namhyung@kernel.org" , "ak@linux.intel.com" , "adrian.hunter@intel.com" , "yao.jin@linux.intel.com" , "tmricht@linux.ibm.com" , "brueckner@linux.ibm.com" , "songliubraving@fb.com" , "gregkh@linuxfoundation.org" , Kim Phillips Cc: "gengdongjiu@huawei.com" , "wxf.wang@hisilicon.com" , "liwei391@huawei.com" , "huawei.libin@huawei.com" , "linux-kernel@vger.kernel.org" , "linux-perf-users@vger.kernel.org" , Al Grant , nd List-Id: linux-perf-users.vger.kernel.org Hi Xiaojun, >> >> What do you mean when the user specifies "event:pp", if the SPE is avail= able, configure and record the spe data directly via the perf event open sy= scall? >> (perf.data itself is the same as using -e arm_spe_0//xxx?) >=20 > I mean, for the perf record, if the user does not add ":pp" to these even= ts, the original process is taken, and if ":pp" is added, the spe process i= s taken. >=20 Yes we think this is the best way to do it considering that SPE has been im= plemented as a separate PMU and it will be very difficult to do it in the K= ernel when the precise_ip attribute is set. I think doing everything in userspace is easiest. This will at least mean t= hat users of Perf don't have to be aware of the details of SPE to get preci= se sample data. So if the user specifies "event:p" when SPE is available, the SPE PMU is au= tomatically configured data is recorded. If the user also specifies -e arm_= spe_0//xxx and wants to do some manual configuration, then that could overr= ide the automatic configuration. James