Hello Godmar -- Many end users prefer to install a Linux distro without patches, custom modules, etc. From the manageability point of view, they would love to have one single system image with no customizations. So, ideally, they (and we) would like to have profiling support as part of the standard kernel.
Sometimes, we can't get kernel-level support for new processor features upstream as fast as we would like. (It's just a reality that the process takes time.) So, the cakm part of the CodeAnalyst distro is an effort to make new features available in a timely way. We did this for Instruction-Based Sampling (IBS). However, Robert Richter, Suravee Suthikulpanit and other teams members continue to work to contribute back to the community even though cakm is available. Yikes, system-wide vs. per-process. There's a simple answer in this case. Before my time, the team chose OProfile as the data collection base for CodeAnalyst on Linux. OProfile was and is system-wide. Some end users prefer system-wide while others prefer per-process/thread. Personally, I would like a solution that provides both -- one reason why we feel pretty good about perfmon2. We're keeping an eye on Performance Counters for Linux (PCL), adoption of PCL by OProfile, etc. It'll take a little while for the whole situation to shake out. -- pj Paul Drongowski AMD CodeAnalyst team -----Original Message----- From: Godmar Back [mailto:god...@gmail.com] Sent: Monday, September 14, 2009 3:51 PM To: Drongowski, Paul Cc: perfmon2-devel@lists.sourceforge.net Subject: Re: [perfmon2] questions about perfmon2 On Mon, Sep 14, 2009 at 10:03 AM, Drongowski, Paul <paul.drongow...@amd.com> wrote: > Hello Godmar -- > > WRT Q6: AMD CodeAnalyst Performance Analyzer (tm) uses OProfile > for data collection on Linux. We also make the source code for > CodeAnalyst available. > > As a team, we look to the Linux/open source community for > OS-level profiling support. Robert Richter from AMD has > contributed perfmon2 support for Instruction-Based Sampling (IBS). > We are also putting back contributions into the OProfile > code base. We have found that it is important for our end users > to have standard profiling support in the kernel (i.e., no > kernel patches). Thus, we always keep an eye on developing > trends. > > I'll be happy to answer any additional questions about > CodeAnalyst. Paul, thanks for this information. I did download CodeAnalyst and saw the custom version of oprofile that is used (I assume that's what cakm is.) Let me clarify, though: you say that AMD prefers to support environment without kernel patches, I assume you mean this literally, in that "no patches," but a custom kernel module is ok? Or do you mean that ultimately, you'd want to avoid any non-standard kernel code, be it patch or module? Second, it is my understanding that oprofile - and, by extension, cakm - support only system-wide profiling and monitoring, rather than a virtualized per-thread approach as is supported by perfctr and perfmon2. Could you elaborate on why that is? Is this a reflection of the difficulties in having standardized support for per-thread counters, or is this a reflection of how you perceive the actual usefulness of per-thread counters? Third, will/does CodeAnalyst support the new perf_counters interface (I assume that's Paul Mackerras's patch?) Thanks! - Godmar ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
