linux-kernel - Re: [PATCH 05/11] perf intel-pt: Use itrace error flags to suppress some errors

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Date:   Thu, 9 Jul 2020 21:22:16 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Andi Kleen <ak@...ux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...hat.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 05/11] perf intel-pt: Use itrace error flags to suppress
 some errors

On 9/07/20 9:13 pm, Adrian Hunter wrote:
> On 9/07/20 8:50 pm, Andi Kleen wrote:
>> On Thu, Jul 09, 2020 at 08:36:22PM +0300, Adrian Hunter wrote:
>>> The itrace "e" option may be followed by a number which has the
>>> following effect for Intel PT:
>>> 	1	Suppress overflow events
>>> 	2	Suppress trace data lost events
>>> The values may be combined by bitwise OR'ing them.
>>>
>>> Suppressing those errors can be useful for testing and debugging
>>> because they are not due to decoding.
>>
>> I suspect it will be useful to more than just decoding and debugging.
>>
>> But the number is not a nice user interface.
>>
>> How about e[....] 
>>
>> like e[ol] 
> 
> Do you mean literally square-brackets? If you were really unlucky you might
> get pathname expansion with that.
> 
>>
>> Also it's a bit unusual that this disables instead of enables, but ok.

What about prefixing each flag with - i.e.

e-o
e-l
e-o-l