From: Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: [PATCH 04/15] xen/trace: add multicall tracing
Date: Tue, 21 Jun 2011 10:11:25 -0700
Message-ID: <4E00D0BD.10509@goop.org>
References: <cover.1308607697.git.jeremy.fitzhardinge@citrix.com> <a0fe82ae10c0a00c31e60ffacbeec6f49eba93a5.1308607697.git.jeremy.fitzhardinge@citrix.com> <20110621135256.GA28229@dumpdata.com>
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To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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>
List-Id: xen-devel@lists.xenproject.org

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?

    J