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Date: Fri, 22 Aug 2014 15:26:41 -0400
From: Eric van Gyzen <eric@vangyzen.net>
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To: freebsd-current@freebsd.org
Subject: Re: ktrace -c behavior
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 <20140822192034.GA71691@funkthat.com>
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On 08/22/2014 15:20, John-Mark Gurney wrote:
> Eric van Gyzen wrote this message on Fri, Aug 22, 2014 at 15:16 -0400:
>> What behavior would you expect from this sequence of commands?
>>
>>     ktrace -tw -p 1234
>>     ktrace -c -p 1234
>>
>> Based on this...
>>
>>      -c      Clear the trace points associated with the specified file
>> or processes.
> and/or just add specified:
> Clear the specified trace points ...

But what if I didn't specify them?

>> ...I would expect the second command to clear the trace point for
>> context switches.  It doesn't.  I have to specify -tw with the -c to get
>> that behavior.  This makes sense; it's just not what I was expecting.
>>
>> Assuming we want to keep this behavior, can we clarify the -c flag in
>> man page?  I would suggest:
>>
>>     If the -t flag is not specified, clear the default set of trace points.
> Maybe we should add a new trace point string that is a (for all).. so
> you can do ktrace -ta -c?

That would be handy.

Eric