From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ming Zhang Date: Mon, 26 Mar 2007 13:30:40 +0000 Subject: Re: how to understand the Q2Q in btt result? Message-Id: <1174915840.3667.4.camel@dhcp-119.ibrix.com> List-Id: References: <1174876819.6887.2.camel@localhost.localdomain> In-Reply-To: <1174876819.6887.2.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-btrace@vger.kernel.org On Sun, 2007-03-25 at 23:51 -0400, Alan D. Brunelle wrote: > Ming Zhang wrote: > > from btt user guide > > > > "Q2Q which measures the time between queue traces in the system. > > This provides some idea as to how quickly IOs are being handed to > > the block IO layer." > > > > does this mean the time between queuing N request and N > > +1 request? > > > > Hi Ming - > > This is the average time between the Q traces being logged. We take the > difference between each succeeding Q trace, and divide the sum by the total. so like block layer idle indicator. maybe a similar D2D will be a nice device indicator as well. > > Alan > > thanks! > > > > Ming > > > > > > - > > To unsubscribe from this list: send the line "unsubscribe linux-btrace" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > - > To unsubscribe from this list: send the line "unsubscribe linux-btrace" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html