[I just realized my initial response didn't go to all] This is really really great information. One more question - what is the difference between average latency and average response time?
Is response time the actual time to client, but latency the actual wallclock time spent executing? In other words, does this mean that the difference is the amount of time a request spends in a pending queue? I'm trying to get a handle on the "best-case" scenario assuming optimal behavior of the scheduler. This is straightforward with single-threaded python (given 200ms wall-clock requests, each instance can at best handle 5 req/sec) but of course much harder to compute with multi-threaded java. A question for Google: What factors go into deciding how many threads an instance can process at once? Is it a constant # or does it depend on how cpu-bound the application is? I make a lot of requests to Facebook and it's not at all unlikely for my app to sit around for hundreds of milliseconds at a time. Jeff On Thu, May 12, 2011 at 3:41 PM, Mike Lawrence <[email protected]> wrote: > reran the Jmeter volume tests to get QPS data... > 1.5.0 GAE SDK. 1000 user threads, each doing 100 web page requests > that issue a couple of backend datastore reads with sessions enabled: > > - without multithreading > - nodes: 40 > - average response time: 1998 ms > - QPS: 6.745 > - Average Latency: 103.9 ms > - Average Memory: 61.2 MBytes > > - with multi threading > - nodes: 8 > - average response time: 962 ms > - QPS: 45.333 > - Average Latency: 148.1 ms > - Average Memory: 71.3 MBytes > > Bottom Line: For my application (Java/Stripes/Slim3), Multi-treading is > twice as fast; > Under the new pricing model, multi-threading is 5 times cheaper (8 nodes > instead of 40 nodes). > Sincerely, Mike Lawrence > > On Thu, May 12, 2011 at 3:46 AM, Jeff Schnitzer <[email protected]> wrote: >> >> This is really neat, thanks for doing this. >> >> Did you track the peak average QPS per instance during this test? I'm >> very curious to know what kind of throughput we can expect for a >> (threaded) java instance. >> >> Thanks, >> Jeff >> >> On Wed, May 11, 2011 at 8:02 PM, Mike Lawrence <[email protected]> >> wrote: >> > here are the jmeter print screens >> > >> > -- >> > You received this message because you are subscribed to the Google >> > Groups >> > "Google App Engine" group. >> > To post to this group, send email to [email protected]. >> > To unsubscribe from this group, send email to >> > [email protected]. >> > For more options, visit this group at >> > http://groups.google.com/group/google-appengine?hl=en. >> > >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Google App Engine" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]. >> For more options, visit this group at >> http://groups.google.com/group/google-appengine?hl=en. >> > > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
