bpo-46740: speedup telnetlib's buffer transfers #31449
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This change leverages the very low frequency of IAC (control) characters: instead of reading/interpreting/appending per character, it's much faster to search them linearly (if any), then copy the data slice to the cooked queue. This was inspired by point 2) in this very old Python-dev topic https://python-dev.python.narkive.com/A86fs3PG/patch-to-telnetlib-py and yields a 5x speedup too. Also calling `socket.recv` with the currently recommended buffer size, 4096.
arhadthedev
reviewed
Feb 20, 2022
| else: | ||
| self.iacseq += c | ||
| c = self.rawq_getchar() | ||
| if c == theNULL: |
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Can theNull be replaced with b'\0'?
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I think theNull should be replaced by NOOPT (they're equal), but it's another topic. This comparison comes from the initial implementation, I've only reindented.
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Note the telnetlib module is deprecated in 3.11 and set for removal in 3.13. See PEP 594 – Removing dead batteries from the standard library and #91217. |
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This patch leverages the very low frequency of IAC (control) characters: instead of reading/interpreting/appending per character, it's much faster to search them linearly (if any), then copy the data (non-IAC) slice to the cooked queue.
rawqindex handling in_next_nonIAC_sliceis almost copied fromrawq_getchar.Also calls
socket.recvwith the currently recommended buffer size, 4096.Patching
process_rawqpatching was inspired by point 2) in this very old Python-dev topichttps://python-dev.python.narkive.com/A86fs3PG/patch-to-telnetlib-py
and yields a 5x speedup too.
https://bugs.python.org/issue46740