[issue27199] TarFile expose copyfileobj bufsize to improve throughput

[Jason Fried]

New submission from Jason Fried:

The default of 16k while good for memory usage it is not well suited for all cases. if we increased this to 4MB we saw a pretty large improvement to tar file creation and extraction on linux servers.

For a 1gb tar file containing 1024 random files each of 10MB in size.
Time Delta for TarFile: 146.3240258693695
Time Delta for FastTarFile 4MB copybufsize: 102.76440262794495
Time Diff: 43.55962324142456 0.2976928975444698

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components: Library (Lib)
files: buftest.py
messages: 267134
nosy: asvetlov, fried, lukasz.langa
priority: normal
severity: normal
status: open
title: TarFile expose copyfileobj bufsize to improve throughput
type: performance
versions: Python 3.5
Added file: http://bugs.python.org/file43158/buftest.py

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue27199>
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