Re: [Qemu-devel] [PATCH v2 2/2] trace: separate MMIO tracepoints from TB-access tracepoints

[Hollis Blanchard <hollis_blanchard@mentor.com>]

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On Wed, 2016-03-02 at 12:12 -0800, Hollis Blanchard wrote:
> Memory accesses to code which has previously been translated into a
> TB show up
> in the MMIO path, so that they may invalidate the TB. It's extremely
> confusing
> to mix those in with device MMIOs, so split them into their own
> tracepoint.
> 
> Signed-off-by: Hollis Blanchard <hollis_blanchard@mentor.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
> It took many hours to figure out why some RAM accesses were coming
> through the
> MMIO path instead of being handled inline in the TBs.
> 
> On IRC, Paolo expressed some concern about performance, but
> ultimately agreed
> that adding one conditional to an already heavy codepath wouldn't
> have much
> impact.
> 
> v2: rename trace_memory_region_ops_tb_read/write to
> trace_memory_region_tb_read/write
> 
Stefan, any further comment here? You sent a Reviewed-by on the
original, but unlike the "include CPU index" patch, you didn't mention
adding this one to https://github.com/stefanha/qemu/commits/tracing.

-- 
Hollis Blanchard <hollis_blanchard@mentor.com>
Mentor Graphics Emulation Division

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