From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 In-Reply-To: References: <582be8e7ec582079560946db64cd8a51@ladd.quanstro.net> Date: Tue, 22 Jun 2010 14:53:57 +0000 Message-ID: From: John Floren To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Content-Type: text/plain; charset=UTF-8 Subject: Re: [9fans] Inducing artificial latency Topicbox-Message-UUID: 363d9112-ead6-11e9-9d60-3106f5b1d025 On Tue, Jun 15, 2010 at 10:14 PM, Gorka Guardiola wrote: > On Wed, Jun 16, 2010 at 12:07 AM, erik quanstrom wrote: >>> Last time I needed something similar, I just run a modified iostats. >> >> how does iostats add latency? >> > > hence the modified. > Hi Gorka Do you still have your modified iostats around? I'm really not sure about the results I get from adding sleeps in the ip code--it takes over twice as long to copy a 10M file between my two test machines (supposed to have 14ms RTT latency added, ping seems to indicate this) than it does to copy from a system running a non-modified kernel to go.cs.bell-labs.com (14ms RTT). I'd like to try running the tests with a different latency method. Thanks John -- "With MPI, familiarity breeds contempt. Contempt and nausea. Contempt, nausea, and fear. Contempt, nausea, fear, and .." -- Ron Minnich