linux-kernel - Re: [PATCH] perf intel-pt: Fix ip compression

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Message-ID: <4cc98408-bf55-439a-e88b-15f1ca57b0ff@intel.com>
Date:	Wed, 10 Aug 2016 11:32:21 +0300
From:	Adrian Hunter <adrian.hunter@...el.com>
To:	Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:	Jiri Olsa <jolsa@...hat.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] perf intel-pt: Fix ip compression

On 20/07/16 12:00, Adrian Hunter wrote:
> June 2015 Intel SDM introduced IP Compression types 4 and 6. Refer section
> 36.4.2.2 Target IP (TIP) Packet - IP Compression.
> 
> Existing Intel PT packet decoder did not support type 4, and got type 6
> wrong.  Because type 3 and type 4 have the same number of bytes, the packet
> 'count' has been changed from being the number of ip bytes to being the
> type code.  That allows the Intel PT decoder to correctly decide whether to
> sign-extend or use the last ip.  However that also meant the code had to be
> adjusted in a number of places.
> 
> Currently hardware is not using the new compression types, so this fix has
> no effect on existing hardware.
> 
> Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
> ---
>  .../perf/util/intel-pt-decoder/intel-pt-decoder.c  | 44 +++++++++++-----------
>  .../util/intel-pt-decoder/intel-pt-pkt-decoder.c   | 24 ++++++++----
>  2 files changed, 40 insertions(+), 28 deletions(-)

Hi

This is outstanding but still applies.

Regards
Adrian