From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Alan D. Brunelle" Date: Wed, 16 Jul 2008 14:43:31 +0000 Subject: Re: [Patch 0/2] blkiomon: I/O monitor based on blktrace data Message-Id: <487E0913.1080502@hp.com> List-Id: References: <1216207358.26621.75.camel@kitka.ibm.com> In-Reply-To: <1216207358.26621.75.camel@kitka.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-btrace@vger.kernel.org Martin Peschke wrote: > On Wed, 2008-07-16 at 09:28 -0400, Alan D. Brunelle wrote: >> Martin Peschke wrote: >>> In order to analyse I/O performance problems which could be reported by >>> customers we want to provide a little monitoring tool. Primarily, we >>> would like to be able look at a history of request size and request >>> latency histograms per device. >>> >>> The D and C traces provided by blktrace are exactly what we need for >>> that purpose. So, running blktrace with appropriate filters (-a option) >>> makes this approach feasible. >>> >>> Patch 1/2 allows users to get binary output from blkparse on stdout. >>> >>> Patch 2/2 contains blkiomon, an I/O monitoring tool, which reads >>> blkparse data from stdin and which periodically writes I/O statistics. >>> >>> I would like to contribute this little tool to the blktrace source tree. >>> I think it would complement blkparse and btt quite well. >>> >>> Martin >> Hi Martin - >> >> Is there some reason why you don't just parse the textual output from >> blkparse itself? [I believe that's what Chris Mason does w/ his >> seekwatcher for example.] > > Hi Alan, > we would like to spend as few CPU cycles as possible. > > Having a little c-program consuming binary data is less expensive than > having blkparse generate textual output which would be parsed by some > script. > > This is a monitoring tool, and there might be millions of requests. Hi Martin - Haven't had time to think this through, but if blktrace is sending binary data to blkparse, why not just replace blkparse w/ blkiomon? Taking data directly from blktrace itself? Alan