From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: Perf support for interpreted and Just-In-Time translated olanguages Date: Wed, 10 Dec 2014 19:09:11 +0100 Message-ID: <20141210180911.GC6759@two.firstfloor.org> References: <1417810736.5098.11.camel@oc0276584878.ibm.com> <20141209203419.GI4189@kernel.org> <87ppbs4h5k.fsf@tassilo.jf.intel.com> <20141209222203.GD8788@kernel.org> <87h9x449vd.fsf@tassilo.jf.intel.com> <1418233295.4953.33.camel@oc0276584878.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from one.firstfloor.org ([193.170.194.197]:40866 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932654AbaLJSJM (ORCPT ); Wed, 10 Dec 2014 13:09:12 -0500 Content-Disposition: inline In-Reply-To: <1418233295.4953.33.camel@oc0276584878.ibm.com> Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Carl Love Cc: Arnaldo Carvalho de Melo , Andi Kleen , Brendan Gregg , Pekka Enberg , "linux-perf-use." > This may be more complex then needed. We really just need to track the > symbol. From talking with the Java experts, they say the reused memory > is almost always from methods that are loaded/used early when > initializing the program. Then the memory gets reused by a method that > runs for the bulk of the time. So by getting a timestamp for when the > symbol was loaded you can then determine the length of time each symbol > was in the anonymous memory. Then just associate the sample with the > symbol that was present in the anonymous memory the longest. You can > also tag the symbol names to say that they reside in the same memory, > ie, the memory was reused. To warn the user that there maybe some > ambiguity in the sample to symbol association. We need a way to transfer the code too. Just symbols is not enough. This needs exact tracking. > The source file and line number information is optionally available from > the jvm via the jvmti complied method load callback. With this > information on the symbol, line number and source file, perf could then > persist the data in an ELF formatted file. I'm not sure ELF/dwarf is the right way to go there. That would be very complex. -Andi -- ak@linux.intel.com -- Speaking for myself only.