On Tue, 03 Sep 2013 18:53:17 +0530, Hemant wrote: > On 09/03/2013 02:47 PM, Masami Hiramatsu wrote: >> (2013/09/03 17:25), Ingo Molnar wrote: >>> * Hemant Kumar Shaw <hks...@linux.vnet.ibm.com> wrote: >>> >>>> This series adds support to perf to list and probe into the SDT markers. >>>> The first patch implements listing of all the SDT markers present in >>>> the ELFs (executables or libraries). The SDT markers are present in the >>>> .note.stapsdt section of the elf. That section can be traversed to list >>>> all the markers. Recognition of markers follows the SystemTap approach. >>>> >>>> The second patch will allow perf to probe into these markers. This is >>>> done by writing the marker name and its offset into the >>>> uprobe_events file in the tracing directory. >>>> Then, perf tools can be used to analyze perf.data file. >>> Please provide a better high level description that explains the history >>> and scope of SDT markers, how SDT markers get into binaries, how they can >>> be used for probing, a real-life usage example that shows something >>> interesting not possible via other ways, etc. >> Indeed, and also I'd like to know what versions of SDT this support, >> and where we can see the technical document of that. As far as I know, >> the previous(?) SDT implementation also involves ugly semaphores. >> Have that already gone?
It seems it's not. I see the SDT v3 document still mentions semaphores. > This link shows an example of marker probing with Systemtap: > https://sourceware.org/systemtap/wiki/AddingUserSpaceProbingToApps I think the link below would be more helpful for us :) http://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation Thanks, Namhyung > > - Markers in binaries : > These SDT markers are present in the ELF in the section named > ".note.stapsdt". > Here, the name of the marker, its provider, type, location, base > address, semaphore address, arguments are present. > We can retrieve these values using the members name_off and desc_off in > Nhdr structure. If these are not enabled, they are present in the ELF > as nop. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/