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Re: Could not use "record btrace" even if I have Intel PT hardware feature
- From: 慕冬亮 <mudongliangabcd at gmail dot com>
- To: "Metzger, Markus T" <markus dot t dot metzger at intel dot com>
- Cc: "gdb at sourceware dot org" <gdb at sourceware dot org>
- Date: Tue, 6 Sep 2016 12:48:06 -0400
- Subject: Re: Could not use "record btrace" even if I have Intel PT hardware feature
- Authentication-results: sourceware.org; auth=none
- References: <CAD-N9QUz19B6Dj2J+=RZ1G4Nfjko3PZD-6_v+hVEsmfjWTR9vg@mail.gmail.com> <A78C989F6D9628469189715575E55B233FFB6E07@IRSMSX104.ger.corp.intel.com>
My best regards to you.
No System Is Safe!
2016-09-06 10:59 GMT-04:00 Metzger, Markus T <email@example.com>:
>> -----Original Message-----
>> From: firstname.lastname@example.org [mailto:email@example.com] On
>> Behalf Of ???
>> Sent: Tuesday, September 6, 2016 4:37 PM
>> To: firstname.lastname@example.org
>> Subject: Could not use "record btrace" even if I have Intel PT hardware feature
> Hello Dongliang,
>> I encounter one problem when I try to leverage Intel PT to do branch tracing.
>> My cpu has Intel PT feature via "grep intel_pt /proc/cpuinfo".
>> $ grep intel_pt /proc/cpuinfo
>> flags : ...intel_pt...
>> $ gdb simple
>> (gdb) b main
>> Breakpoint 1 at 0x40050c
>> (gdb) r
>> Starting program: .../Work/Projects/simple
>> Breakpoint 1, 0x000000000040050c in main ()
>> (gdb) record btrace
>> Target does not support branch tracing.
>> (gdb) record btrace pt
>> GDB does not support Intel Processor Trace.
> You need a kernel that supports it (4.1+) and you need a GDB that supports it.
I am using Debian Testing with linux kernel 4.6.0-1 and gdb 7.11.1-2
> Newer Linux distributions should already provide GDB with Intel PT support. If
> your distribution doesn't or if you want to build GDB yourself, please configure
> it with "--with-intel-pt".
I have installed libipt-dev and libipt1 packages.
> If your Linux distribution does not provide libipt(-devel), you may need to
> build it yourself. You can get the sources from here:
> You may also need to configure GDB with "--with-libipt-prefix=<path-to-libipt>"
> if you don't (want to) install libipt in a standard place.
> You may further need to install kernel headers - GDB needs
And I have checked the existence of /usr/include/linux/perf_event.h.
Should I reboot my Debian to make kernel module for Intel PT effective?
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