Tweaks to reduce memory use of short commands #5837
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This avoids creation of most Charset encoders, decoders, buffers, and some intermediate byte[] and char[] instances created at boot and by the parser.
The yacc logic did not use the out variable. The ripper logic was simple to change to use a field. This eliminates allocation of thousands of Encoding[1] during gem list.
Many arrays in the system are single elements, both in user code and within our AST to represent things like argument lists. This logic reduces the amount of wasted Node[] instances when a given ListNode will only ever contain one element. If a ListNode with a single element is grown, this logic returns to a Node[] from then on. This change, tested against `--dev -S gem list` reduce Node[] use by the following numbers: Before: * Node[] allocated: 48002 (1536064 bytes) * Node[] retained: 24900 (796800 bytes) After: * Node[] allocated: 12390 (612576 bytes) * Node[] retained: 6142 (303704 bytes)
The former pattern caused a StringBuilder and accompanying buffer to be instantiated just to append a character and turn the buffer into a String, at a cost of another additional char[]. String.valueOf allocates only the one-element char[] and the String object itself.
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I have re-pushed this with the failing source position patch moved to #5838. |
kares
reviewed
Aug 18, 2019
kares
approved these changes
Aug 18, 2019
This was inserted to detect if this Iterator implementation were ever used. None of my tests produced any output, and it apparently did not interfere with any tests in CI. Maybe it was needed before but it is apparently not used now.
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I'm going to go ahead and merge this. @enebo any review issues you find I will patch later. |
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This is a set of memory/alloc-reducing experiments that can be merged or cherry-picked as appropriate.