From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH 04/15] xen/trace: add multicall tracing
Date: Tue, 21 Jun 2011 13:21:42 -0400
Message-ID: <20110621172142.GA29370@dumpdata.com>
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To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Xen Devel <Xen-devel@lists.xensource.com>, Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@redhat.com>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
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On Tue, Jun 21, 2011 at 10:11:25AM -0700, Jeremy Fitzhardinge wrote:
> On 06/21/2011 06:52 AM, Konrad Rzeszutek Wilk wrote:
> >> +TRACE_EVENT(xen_mc_entry,
> >> +	    TP_PROTO(struct multicall_entry *mc, unsigned nargs),
> >> +	    TP_ARGS(mc, nargs),
> >> +	    TP_STRUCT__entry(
> >> +		    __field(unsigned short, op)
> >> +		    __field(unsigned short, nargs)
> >> +		    __array(unsigned long, args, 6)
> > Not 'unsigned long' for op?
> 
> I wanted to save space in the trace buffer.  I think hypercall numbers
> are all small?

OK, but then the next entry (not shown here) used 'unsigned long' for the 'op' as well.