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    SubjectRe: [PATCH 07/12] perf_events: add LBR software filter support for Intel X86 (v2)
    On Fri, 2011-10-14 at 14:37 +0200, Stephane Eranian wrote:
    > This patch adds an internal sofware filter to complement
    > the (optional) LBR hardware filter.
    > The software filter is necessary:
    > - as a substitute when there is no HW LBR filter (e.g., Atom, Core)
    > - to complement HW LBR filter in case of errata (e.g., Nehalem/Westmere)
    > - to provide finer grain filtering (e.g., all processors)
    > Sometimes, the LBR HW filter cannot distinguish between two types
    > of branches. For instance, to capture syscall as CALLS, it is necessary
    > to enable the LBR_FAR filter which will also capture JMP instructions.
    > Thus, a second pass is necessary to filter those out, this is what the
    > SW filter can do.
    > The SW filter is built on top of the internal x86 disassembler. It
    > is a best effort filter especially for user level code. It is subject
    > to the availability of the text page of the program.
    > The SW filter is enabled on all Intel X86 processors. It is bypassed
    > when the user is capturing all branches at all priv levels.

    This patch is very seriously whitespace challenged.

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      Last update: 2011-12-05 23:33    [W:0.336 / U:2.016 seconds]
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