Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752118AbcDRQNS (ORCPT ); Mon, 18 Apr 2016 12:13:18 -0400 Received: from smtprelay0133.hostedemail.com ([216.40.44.133]:54302 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751552AbcDRQNR (ORCPT ); Mon, 18 Apr 2016 12:13:17 -0400 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::::::::::::::::,RULES_HIT:41:355:379:541:599:800:960:973:988:989:1260:1277:1311:1313:1314:1345:1359:1431:1437:1515:1516:1518:1534:1540:1593:1594:1711:1730:1747:1777:1792:2198:2199:2393:2553:2559:2562:2740:3138:3139:3140:3141:3142:3308:3352:3622:3865:3866:3867:3868:3870:3871:3872:3873:3874:5007:6119:6120:6261:6742:7875:7901:7903:8660:10004:10400:10848:10967:11026:11232:11658:11914:12043:12517:12519:12740:13069:13138:13148:13230:13231:13311:13357:13439:13618:14096:14097:14180:14181:14659:21060:21080:21324:30054:30064:30090:30091,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:2,LUA_SUMMARY:none X-HE-Tag: stew01_9091c4305810a X-Filterd-Recvd-Size: 2122 Date: Mon, 18 Apr 2016 12:13:11 -0400 From: Steven Rostedt To: Alexei Starovoitov Cc: Peter Zijlstra , "David S . Miller" , Ingo Molnar , Daniel Borkmann , Arnaldo Carvalho de Melo , Wang Nan , Josef Bacik , Brendan Gregg , , , Subject: Re: [PATCH net-next 0/8] allow bpf attach to tracepoints Message-ID: <20160418121311.10c88768@gandalf.local.home> In-Reply-To: <1459831974-2891931-1-git-send-email-ast@fb.com> References: <1459831974-2891931-1-git-send-email-ast@fb.com> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 944 Lines: 20 On Mon, 4 Apr 2016 21:52:46 -0700 Alexei Starovoitov wrote: > Hi Steven, Peter, > > last time we discussed bpf+tracepoints it was a year ago [1] and the reason > we didn't proceed with that approach was that bpf would make arguments > arg1, arg2 to trace_xx(arg1, arg2) call to be exposed to bpf program > and that was considered unnecessary extension of abi. Back then I wanted > to avoid the cost of buffer alloc and field assign part in all > of the tracepoints, but looks like when optimized the cost is acceptable. > So this new apporach doesn't expose any new abi to bpf program. > The program is looking at tracepoint fields after they were copied > by perf_trace_xx() and described in /sys/kernel/debug/tracing/events/xxx/format Does this mean that ftrace could use this ability as well? As all the current filtering of ftrace was done after it was copied to the buffer, and that was what you wanted to avoid. -- Steve