From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 4EB8C6B004F for ; Tue, 4 Aug 2009 16:05:49 -0400 (EDT) Date: Tue, 4 Aug 2009 22:35:26 +0200 From: Ingo Molnar Subject: Re: [PATCH 4/4] tracing, page-allocator: Add a postprocessing script for page-allocator-related ftrace events Message-ID: <20090804203526.GA8699@elte.hu> References: <1249409546-6343-1-git-send-email-mel@csn.ul.ie> <1249409546-6343-5-git-send-email-mel@csn.ul.ie> <20090804112246.4e6d0ab1.akpm@linux-foundation.org> <20090804195717.GA5998@elte.hu> <20090804131818.ee5d4696.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090804131818.ee5d4696.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: penberg@cs.helsinki.fi, a.p.zijlstra@chello.nl, fweisbec@gmail.com, rostedt@goodmis.org, mel@csn.ul.ie, lwoodman@redhat.com, riel@redhat.com, peterz@infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: * Andrew Morton wrote: > On Tue, 4 Aug 2009 21:57:17 +0200 > Ingo Molnar wrote: > > > Let me demonstrate these features in action (i've applied the > > patches for testing to -tip): > > So? The fact that certain things can be done doesn't mean that > there's a demand for them, nor that anyone will _use_ this stuff. c'mon Andrew ... Did you never want to see whether firefox is leaking [any sort of] memory, and if yes, on what callsites? Try something like on an already running firefox context: perf stat -e kmem:mm_page_alloc \ -e kmem:mm_pagevec_free \ -e kmem:mm_page_free_direct \ -p $(pidof firefox-bin) sleep 10 ... and "perf record" for the specific callsites. this perf stuff is immensely flexible and a very unixish abstraction. The perf.data contains timestamped trace entries of page allocations and freeing done. [...] > It would be nice to at least partially remove the vmstat/meminfo > infrastructure but I don't think we can do that? at least meminfo is an ABI for sure - vmstat too really. But we can stop adding new fields into obsolete, inflexible and clearly deficient interfaces, and we can standardize new instrumentation to use modern instrumentation facilities - i.e. tracepoints and perfcounters. I'm not saying to put a tracepoint on every second line of the kernel, but obviously Mel and Rik wanted this kind of info because they found it useful in practice. Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org