> My perl is 5.36.3 on cygwin ... I just ran it on another system (Linux) on the same file ...
> and got 0.675398 read lines from in-memory file and do RE (vs 48.796606 on cygwin)

Wow, that is such a massive difference, I suspect something's seriously wrong with your cygwin perl v5.36.3 environment ... so I suggest you run your test program on cygwin with various tools to try to understand why on earth it's taking so long. Some tools you might try:

Other suggestions welcome. I suspect a system level tool (such as VTune) is the best bet in this case, hopefully it will reveal something glaringly wrong (as it did for me here).

For future reference, posting a test program using Benchmark, that anyone can run with zero effort, is the ideal way to get help on these sorts of performance problems (see Fastest way to lookup a point in a set (update: and Re: Confused by RegEx count by choroba) for examples).

See also: Code Optimization and Performance References (and Memory Tools References) 

👁️🍾👍🦟

In reply to Re^3: RE on lines read from in-memory scalar is very slow by eyepopslikeamosquito
in thread RE on lines read from in-memory scalar is very slow by Danny

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