From mboxrd@z Thu Jan 1 00:00:00 1970 From: Namhyung Kim Subject: Re: [PATCH v3 2/3] perf: Userspace event Date: Wed, 05 Nov 2014 15:36:31 +0900 Message-ID: <878ujqw3v4.fsf@sejong.aot.lge.com> References: <1415060918-19954-1-git-send-email-pawel.moll@arm.com> <1415060918-19954-3-git-send-email-pawel.moll@arm.com> <87ppd35vbk.fsf@sejong.aot.lge.com> <1415119331.24819.19.camel@arm.com> <20141104184031.GM10501@worktop.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <20141104184031.GM10501-IIpfhp3q70z/8w/KjCw3T+5/BudmfyzbbVWyRVo5IupeoWH0uzbU5w@public.gmane.org> (Peter Zijlstra's message of "Tue, 4 Nov 2014 19:40:31 +0100") Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Peter Zijlstra Cc: Pawel Moll , Namhyung Kim , Richard Cochran , Steven Rostedt , Ingo Molnar , Paul Mackerras , Arnaldo Carvalho de Melo , John Stultz , Masami Hiramatsu , Christopher Covington , David Ahern , Thomas Gleixner List-Id: linux-api@vger.kernel.org Hi Peter and Pawel, On Tue, 4 Nov 2014 19:40:31 +0100, Peter Zijlstra wrote: > On Tue, Nov 04, 2014 at 04:42:11PM +0000, Pawel Moll wrote: >> >> 1. I'm wrong and the record doesn't have to be padded to make it 8 bytes >> aligned. Then I can drop the additional size field. > > No, you're right, we're supposed to stay 8 byte aligned. > >> 2. I could impose a limitation on the prctl API that the data size must >> be 8 bytes aligned. Bad idea in my opinion, I'd rather not. > > Agreed. > >> 3. The additional size (for the data part) field stays. Notice that >> PERF_SAMPLE_RAW has it as well :-) > > Right, with binary data there is no other day. With \0 terminated > strings there won't be a problem, but I think we decided we wanted to > allow any binary blow. Ah, I missed that. Thank you guys for explanation. Thanks, Namhyung