From: Andi Kleen <ak@linux.intel.com>
To: David Carrillo-Cisneros <davidcc@google.com>
Cc: linux-kernel@vger.kernel.org, "x86@kernel.org" <x86@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
"Yan, Zheng" <zheng.z.yan@intel.com>,
Kan Liang <kan.liang@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH 1/3] perf/x86/intel: output LBR support statement after validation
Date: Thu, 2 Jun 2016 09:04:28 -0700 [thread overview]
Message-ID: <20160602160428.GR22049@tassilo.jf.intel.com> (raw)
In-Reply-To: <1464835323-33872-2-git-send-email-davidcc@google.com>
I don't think the context switch support is really needed. It's only
needed for saving/restoring LBRs, and we only do that with LBR callstacks.
In any other LBR mode that LBRs are only flushed on context switch
But LBR callstacks will never put kernel addresses into the LBRs
because they are forced to set a ring 3 filter. So you can't have
kernel addresses in the LBR when saving/restoring them
(unless I missed some case)
Dropping that will likely simplify the patch somewhat.
-Andi
next prev parent reply other threads:[~2016-06-02 16:04 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-02 2:42 [PATCH 0/3] fix MSR_LAST_BRANCH_FROM Haswell support David Carrillo-Cisneros
2016-06-02 2:42 ` [PATCH 1/3] perf/x86/intel: output LBR support statement after validation David Carrillo-Cisneros
2016-06-02 8:21 ` Peter Zijlstra
2016-06-02 16:04 ` Andi Kleen [this message]
2016-06-02 17:28 ` Stephane Eranian
2016-06-06 1:59 ` Andi Kleen
2016-06-08 7:27 ` Stephane Eranian
2016-06-08 9:08 ` Andi Kleen
2016-06-02 2:42 ` [PATCH 2/3] perf/x86/intel: fix for MSR_LAST_BRANCH_FROM_x quirk when no TSX David Carrillo-Cisneros
2016-06-02 8:23 ` Peter Zijlstra
2016-06-02 8:37 ` Peter Zijlstra
2016-06-02 8:53 ` Peter Zijlstra
[not found] ` <CALcN6mhMsNHgRVuYmYsE+O+Neq6PcaDy1-ARzBd=Vej=0rHr0Q@mail.gmail.com>
2016-06-03 9:21 ` Peter Zijlstra
2016-06-02 8:54 ` Peter Zijlstra
2016-06-02 8:55 ` Peter Zijlstra
2016-06-02 16:07 ` Andi Kleen
2016-06-02 2:42 ` [PATCH 3/3] perf, perf/tool: trigger lbr_from signext bug David Carrillo-Cisneros
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160602160428.GR22049@tassilo.jf.intel.com \
--to=ak@linux.intel.com \
--cc=davidcc@google.com \
--cc=eranian@google.com \
--cc=kan.liang@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=x86@kernel.org \
--cc=zheng.z.yan@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).