From: Mark Kettenis <mark.kettenis@xs4all.nl>
To: markus.t.metzger@intel.com
Cc: jan.kratochvil@redhat.com, palves@redhat.com, tromey@redhat.com,
gdb-patches@sourceware.org, markus.t.metzger@gmail.com,
markus.t.metzger@intel.com
Subject: Re: [patch v6 12/12] btrace, x86: disable on some processors
Date: Mon, 17 Dec 2012 17:11:00 -0000 [thread overview]
Message-ID: <201212171711.qBHHBADJ018585@glazunov.sibelius.xs4all.nl> (raw)
In-Reply-To: <1355760101-26237-13-git-send-email-markus.t.metzger@intel.com>
> From: <markus.t.metzger@intel.com>
> Date: Mon, 17 Dec 2012 17:01:41 +0100
>
> From: Markus Metzger <markus.t.metzger@intel.com>
>
> LBR, BTM, or BTS records may have incorrect branch "from" information afer an
> EIST transition, T-states, C1E, or Adaptive Thermal Throttling (AAJ122).
>
> This results in sporadic test fails. Disable btrace on those processors.
>
> 2012-12-17 Markus Metzger <markus.t.metzger@intel.com>
>
> * common/linux-btrace.c (linux_supports_btrace): Add cpuid check.
I think this approach is a reasonable compromise. However, AFAICT the
linux_supports_btrace() is called unconditionally. Therefore this
will break GDB on old CPUs that don't implement the cpuid
instructions. And AFAIK the family/model values are specific to
Intel, so you should check that you're on an Intel CPU before
interpreting these values. And I still think you should check whether
the kernel supports BTS on the CPU you're running on first before
disabling it on certain CPUs.
next prev parent reply other threads:[~2012-12-17 17:11 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-17 16:02 [patch v6 00/12] branch tracing support for Atom markus.t.metzger
2012-12-17 16:02 ` [patch v6 01/12] thread, btrace: add generic branch trace support markus.t.metzger
2012-12-17 16:02 ` [patch v6 08/12] gdbserver, btrace: add generic btrace support markus.t.metzger
2012-12-17 20:43 ` Jan Kratochvil
2012-12-17 16:02 ` [patch v6 12/12] btrace, x86: disable on some processors markus.t.metzger
2012-12-17 17:11 ` Mark Kettenis [this message]
2012-12-19 16:13 ` Metzger, Markus T
2012-12-19 16:36 ` Mark Kettenis
2012-12-21 10:38 ` Jan Kratochvil
2012-12-17 17:37 ` H.J. Lu
2012-12-19 15:58 ` Metzger, Markus T
2012-12-17 20:35 ` Jan Kratochvil
2012-12-17 16:02 ` [patch v6 06/12] remote, btrace: add branch trace remote ops markus.t.metzger
2012-12-17 19:57 ` Jan Kratochvil
2012-12-17 16:02 ` [patch v6 02/12] cli, btrace: add btrace cli markus.t.metzger
2012-12-17 18:32 ` Jan Kratochvil
2012-12-18 7:36 ` Metzger, Markus T
2012-12-18 8:35 ` Jan Kratochvil
2012-12-18 9:04 ` Jan Kratochvil
2012-12-18 9:11 ` Metzger, Markus T
2012-12-17 16:02 ` [patch v6 09/12] gdbserver, linux, btrace: add btrace support for linux-low markus.t.metzger
2012-12-17 16:03 ` [patch v6 11/12] test, btrace: more branch tracing tests markus.t.metzger
2012-12-17 16:03 ` [patch v6 07/12] btrace, doc: document remote serial protocol markus.t.metzger
2012-12-17 16:03 ` [patch v6 03/12] linux, btrace: perf_event based branch tracing markus.t.metzger
2012-12-17 16:03 ` [patch v6 05/12] xml, btrace: define btrace xml document style markus.t.metzger
2012-12-17 19:53 ` Jan Kratochvil
2012-12-18 7:43 ` Metzger, Markus T
2012-12-17 16:03 ` [patch v6 10/12] test, btrace: add branch tracing tests markus.t.metzger
2012-12-17 20:26 ` Jan Kratochvil
2012-12-17 16:03 ` [patch v6 04/12] linux, i386, amd64: enable btrace for 32bit and 64bit linux native markus.t.metzger
2012-12-17 18:45 ` [patch v6 00/12] branch tracing support for Atom Jan Kratochvil
2012-12-17 19:34 ` Tom Tromey
2012-12-18 7:24 ` Metzger, Markus T
2012-12-18 9:20 ` Jan Kratochvil
2012-12-18 10:14 ` Metzger, Markus T
2012-12-18 13:55 ` Jan Kratochvil
2012-12-19 9:59 ` Metzger, Markus T
2012-12-19 12:13 ` Mark Kettenis
2012-12-19 12:37 ` Jan Kratochvil
2012-12-20 7:17 ` Jan Kratochvil
2012-12-20 9:14 ` Metzger, Markus T
2012-12-20 11:43 ` Jan Kratochvil
2012-12-20 15:20 ` Metzger, Markus T
2012-12-21 19:12 ` Jan Kratochvil
2012-12-22 13:08 ` Jan Kratochvil
2013-01-01 16:35 ` Jan Kratochvil
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