Hi Jeff, Yes, I think it is down to network topology. I have been pointed at the Java get latency figures that I had not realised were accessible before.
I have put together a test set of interactions, and I was surprised to discover that when I measured the latency using javascript it is typically 160 - 200ms (far better than the 1 second I claimed in my original post). This certainly enforces what you say about perceived user experience. Of course the user delay will be a little more due to browser refresh, but I was clearly way out in my subjective estimation. I get ~150ms on an appspot.com ping, so this completely explains the delays (I have also asked a few UK friends to ping appspot and they see similar figures). Interestingly this is pretty much what I get when I ping google.com (but mail.google.com is very quick at 20ms). I'll post a link to the test app in a bit. - Martyn On Aug 12, 7:26 pm, "Jeff S (Google)" <j...@google.com> wrote: > Hi Martyn, > > The network topology between you and the App Engine server could also be a > factor in this latency, so I might start by checking there. I'm also > wondering how frequently you are making these requests. We're certainly > interested in doing what we can to reduce overall latency, we've generally > found that user perceived latency has a big impact and, to the user, it > really doesn't matter which part of the experience is slow and they don't > always have a way of knowing. > > Cheers, > > Jeff > > On Tue, Aug 11, 2009 at 2:08 AM, Martyn <martyn.cutc...@googlemail.com>wrote: > > > > > > > I experience round-trip latency from a browser of around one second. > > (My request log indicates < 25ms for many requests in the application) > > > Is this explainable/expected/considered acceptable? It would > > certainly make "as you type" updates as per the Wave demos hard to > > emulate! > > > I am using Java, so maybe this is not such a problem for python apps > > and is related to routing to the JVM, I don't know. > > > Should I be able to plan for significantly reduced request latency in > > the near future? > > > - Martyn --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
