[Python-Dev] Opcode cache in ceval loop

[Serhiy Storchaka]

On 01.02.16 21:10, Yury Selivanov wrote:
> To measure the max/average memory impact, I tuned my code to optimize
> *every* code object on *first* run.  Then I ran the entire Python test
> suite.  Python test suite + standard library both contain around 72395
> code objects, which required 20Mb of memory for caches.  The test
> process consumed around 400Mb of memory.  Thus, the absolute worst case
> scenario, the overhead is about 5%.

Test process consumes such much memory because few tests creates huge 
objects. If exclude these tests (note that tests that requires more than 
1Gb are already excluded by default) and tests that creates a number of 
threads (threads consume much memory too), the rest of tests needs less 
than 100Mb of memory. Absolute required minimum is about 25Mb. Thus, the 
absolute worst case scenario, the overhead is about 100%.