From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754755AbbCBTcB (ORCPT ); Mon, 2 Mar 2015 14:32:01 -0500 Received: from smtprelay0217.hostedemail.com ([216.40.44.217]:35149 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753865AbbCBTcA (ORCPT ); Mon, 2 Mar 2015 14:32:00 -0500 X-Session-Marker: 6E657665747340676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::::::::,RULES_HIT:41:355:379:541:599:800:960:968:973:982:988:989:1260:1277:1311:1313:1314:1345:1359:1431:1437:1515:1516:1518:1534:1541:1593:1594:1711:1730:1747:1777:1792:2393:2553:2559:2562:2692:2693:3138:3139:3140:3141:3142:3353:3622:3865:3866:3867:3868:3870:3871:3872:3873:3874:4250:5007:6119:6261:7875:7903:10004:10400:10848:10967:11026:11232:11658:11914:12043:12438:12517:12519:12663:12740:13069:13075:13311:13357:14096:14097:21080:21088,0,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 X-HE-Tag: feet50_688c5ca292b02 X-Filterd-Recvd-Size: 2800 Date: Mon, 2 Mar 2015 14:31:57 -0500 From: Steven Rostedt To: Alexei Starovoitov Cc: Tom Zanussi , Masami Hiramatsu , Namhyung Kim , Andi Kleen , LKML , Ingo Molnar , Arnaldo Carvalho de Melo Subject: Re: [PATCH v2 00/15] tracing: 'hist' triggers Message-ID: <20150302143157.6947d901@gandalf.local.home> In-Reply-To: References: X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.25; 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 On Mon, 2 Mar 2015 11:14:54 -0800 Alexei Starovoitov wrote: > I think we both want to see in-kernel aggregation. > This 'hist' stuff is trying to do counting and even map sorting > in the kernel, whereas with bpf programs I'm moving > all of these decisions to user space. > I understand your desire to avoid any user level scripts > and do everything via 'cat' and debugfs, but imo that's > very limiting. I think it's better to do slim user space > scripting language that can translate to bpf even in > embedded setups. Then users will be able to aggregate > whatever they like, whereas with 'hist' approach > they're limited to simple counters. > trace_events_trigger.c - 1466 lines - that's quite a bit > of code that will be rarely used. Kinda goes counter > to embedded argument. Why add this to kernel > when bpf programs can do the same on demand? At Collab, a lot of people came to me telling me they love the debugfs system. Because it's everywhere they go. You remove that, you remove most users (including myself). > Also the arguments about stable ABI apply as well. > The format of 'hist' file would need to be stable, so will > be hard to extend it. With bpf programs doing aggregation > the kernel ABI exposure is much smaller. I disagree with this statement. > So would you consider working together on adding > clean bpf+tracepoints infra and corresponding > user space bits? > We can have small user space parser/compiler for > 'hist:keys=common_pid.execname,id.syscall:vals=hitcount' > strings that will convert it into bpf program and you'll > be able to use it in embedded setups ? Make sure it also works on android. -- Steve