On Thu, 3 Feb 2022 at 23:16, Greg Ewing <greg.ew...@canterbury.ac.nz> wrote: > > On 4/02/22 5:07 am, Albert-Jan Roskam wrote: > > On Feb 3, 2022 17:01, Dan Stromberg <drsali...@gmail.com> wrote: > > > > What profiler do you recommend > > If it runs for that long, just measuring execution time should > be enough. Python comes with a "timeit" module to help with > that, or you can use whatever your OS provides (e.g. the > "time" shell command in unices).
Yes, exactly. It's important to distinguish between timing or benchmarking as compared to profiling. When you use a profiler it does not usually give an accurate representation of the time taken by the same code when the profiler is not running because of the overhead added by the profiler itself. The purpose of the profiler is instead to give lots of information that can help you to *think* about how to make the code faster (e.g. what proportion of time is spent in different functions or how many times is a function called etc). This information is useful for considering at a *high level* what parts of the code could be improved to make it faster by e.g. calling a particular function less or making that function faster. The timeit module can be used to time micro-operations i.e. things that take nanoseconds or maybe milliseconds. It repeats an operation in a loop which is often needed to get reliable timings for things that are otherwise too fast to reliably time from a single run. It can give information that helps to identify good approaches to try at a *low level* e.g. when optimising a single line of code. If you want to *evaluate* whether or not a change actually makes your *whole* program faster you should just run your code normally but time how long it takes (which is what the unix "time" command does). You can also use time.time() from Python for this. Profilers and timeit help to identify ways to speed up your code but should not be used as the way to assess the final impact of the changes you make to a long running program. -- Oscar -- https://mail.python.org/mailman/listinfo/python-list
