Hi Carsten, You're correct that the best way to do this is to run the code on App Engine and see just how many CPU cycles your requests require. You don't need a load test, however: You can see exactly how many CPU milliseconds a request required by looking at the logs page of the admin console. Just run a few tests to get an average. Note that the first request to a runtime instance will generally cost more than subsequent ones; you may want to make this clear by logging something in a request when it's the first one, so you can tell them apart easily.
CPU cycles are infuriatingly difficult to convert, with different architectures having different characteristics, even down to per-operation differences. What did you have in mind when you suggest it's something we need to improve? -Nick Johnson On Sun, Jun 14, 2009 at 10:51 AM, CarstenN <[email protected]> wrote: > > I'm interested in the same. I know that you can get the clock-cycles a > request used so far by calling quota.get_request_cpu_usage(), but I > don't find this to be very useful as an absolute measurement. > > The docs state (on the quota page): 'CPU time is reported in > "seconds," which is equivalent to the number of CPU cycles that can be > performed by a 1.2 GHz Intel x86 processor in that amount of time. The > actual number of CPU cycles spent varies greatly depending on > conditions internal to App Engine, so this number is adjusted for > reporting purposes using this processor as a reference measurement.' > > So, in theory, a CPU second would be about 1.2 billion clock cycles. > But I highly doubt it works that way in practice. So my current > solution is to just implement the CPU intensive parts and hit them > with a load test (And have a backup plan in case the CPU usage > policies change again). > > IMHO this is something that Google really needs to improve. App Engine > does lack transparency in some areas - and given that it's a product > meant to appeal to engineers that's a real flaw. > > On Jun 14, 2:13 am, mclovin <[email protected]> wrote: > > I wanted to see if an app would be cost effective to deploy on > > google's app engine and i guess one of the main areas i am concerned > > with is CPU usage. Is there a way to calculate how many CPU hours it > > will use on Google's servers? (the app is already running on my > > computer via django) I dont think an hour of CPU time on my computer > > is comparable to a "CPU Hour" but I guess I may be wrong. > > > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
