From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 4441 invoked by alias); 23 Jul 2014 14:42:38 -0000 Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org Received: (qmail 4357 invoked by uid 89); 23 Jul 2014 14:42:37 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.7 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Wed, 23 Jul 2014 14:42:36 +0000 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s6NEgTAF006034 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 23 Jul 2014 10:42:29 -0400 Received: from fche.csb (vpn-61-251.rdu2.redhat.com [10.10.61.251]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s6NEgS2O005902; Wed, 23 Jul 2014 10:42:28 -0400 Received: by fche.csb (Postfix, from userid 2569) id 8D36B58508; Wed, 23 Jul 2014 10:42:27 -0400 (EDT) To: Nathan Scott Cc: David Smith , pcp@oss.sgi.com, Systemtap List Subject: Re: systemtap/pcp integration References: <53C83CB9.3020808@redhat.com> <861139755.14608867.1405992742567.JavaMail.zimbra@redhat.com> <53CE7A2E.6010306@redhat.com> <181878137.16180790.1406111368167.JavaMail.zimbra@redhat.com> From: fche@redhat.com (Frank Ch. Eigler) Date: Wed, 23 Jul 2014 14:42:00 -0000 In-Reply-To: <181878137.16180790.1406111368167.JavaMail.zimbra@redhat.com> (Nathan Scott's message of "Wed, 23 Jul 2014 06:29:28 -0400 (EDT)") Message-ID: User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-SW-Source: 2014-q3/txt/msg00077.txt.bz2 nathans wrote: > Got it. So, next I'm wondering... what is [the module name] doing > here, in this interface between systemtap/pcp? [...] systemtap is not a single bundle of instrumentation. It is a tool for building/running many instrumentation scripts. The unique module name lets the kernel tell them apart. > In MMV (and the existing pmdammv, in particular), the basename of > these files is used to form the first component of the metric > namespace [...] That's a most straightforward possibility, though not the most user-friendly one, as the module names change from run to run. Perhaps the systemtap script could propose a pmns prefix via an auxiliary file. > [...] I guess you'd have to then completely start over again [for > JSON] Yes, but the systemtap side of this would be pretty trivial. Printing JSON strings is easy. > (for ... reasons?) Other messages in the thread pointed out some reasons, namely: - ability to generalize to event traffic, not just sampled metrics - robustness, by avoiding fragile C code > [...] I haven't seen any other need for a generic JSON interface > [...] In previous notes it was pointed out that JSON is a good encoding for stats data, because it is exported by other tools like ceph, zabbix, and many others including > [...] elasticsearch [...] So the proposal is to think about a single general JSON PMDA that can be configured to bridge data from multiple JSON-emitting applications, including systemtap scripts. - FChE