Bug 1256513
| Summary: | Support libipt for Broadwell+ Intel(R) Processor Trace | ||
|---|---|---|---|
| Product: | Red Hat Developer Toolset | Reporter: | Jan Kratochvil <jan.kratochvil> |
| Component: | gdb | Assignee: | Jan Kratochvil <jan.kratochvil> |
| Status: | CLOSED ERRATA | QA Contact: | Sergey Kolosov <skolosov> |
| Severity: | unspecified | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | DTS 4.0 RHEL 7 | CC: | jan.kratochvil, lwang, mbenitez, mcermak, mnewsome, ohudlick, palves, skolosov |
| Target Milestone: | alpha | ||
| Target Release: | 6.0 | ||
| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | devtoolset-6-gdb-7.11.1-83.el7 | Doc Type: | Bug Fix |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2016-11-15 10:11:46 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 1270539 | ||
| Bug Blocks: | |||
Fedora Rawhide libipt new package (.spec file) for review: Bug 1258572 So technically I can include it into DTS-4.0. gdb.rawhide+libipt.rawhide are built: https://koji.fedoraproject.org/koji/taskinfo?taskID=10944184 gdb.rawhide https://koji.fedoraproject.org/koji/buildinfo?buildID=682567 libipt.rawhide "intel_pt_interrupt" is still not found in: kernel-2.6.32-653.el6 But it is now present thanks to RHEL-7.3 kernel Bug 1270539 in: kernel-3.10.0-489.el7 It requires Intel Broadwell or higher where does exist: /sys/bus/event_source/devices/intel_pt/type and also there is in CPU flags: grep -w intel_pt /proc/cpuinfo Successfully tested it in Beaker with kernel-hw loaned machine: dell-per730-02.khw.lab.eng.bos.redhat.com kernel-3.10.0-489.el7.x86_64 Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHBA-2016-2737.html |
Description of problem: DTS/Fedora/RHEL GDB does not yet support new functionality of branch tracing available in Broadwell + Skylake CPUs: https://sourceware.org/ml/gdb-patches/2015-07/msg00010.html http://post-office.corp.redhat.com/archives/debug-list/2015-August/msg00006.html https://sourceware.org/gdb/onlinedocs/gdb/Process-Record-and-Replay.html - record btrace pt To get the feature one could either package new rpm libipt or bundle libipt with GDB (either dynamically or statically). libipt will be a new Fedora package in Fedora Rawhide but that does not seem to be quick enough for DTS-4.0. Version-Release number of selected component (if applicable): devtoolset-4-gdb-7.9.90.20150717-7.el7 How reproducible: Always. Steps to Reproduce: gdb -ex start -ex 'record btrace pt' Actual results: Target does not support branch tracing. Expected results: <nothing> ("info record" then should display PT is active) Additional info: