path: root/io.c
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authornormal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2018-01-05 20:48:55 (GMT)
committernormal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2018-01-05 20:48:55 (GMT)
commita55abcc0ca6f628fc05304f81e5a044d65ab4a68 (patch)
tree9b0f3d3bb2f81c3797f666dd4cc25535a3f8fdc2 /io.c
parentfb7ed3b32f82d807c5a6232d8c90ed56b4739739 (diff)
zlib: reduce garbage on gzip writes (deflate)
Zlib::GzipWriter generated large amounts of garbage from (struct zstream).input. Reuse the .input field when it is hidden, and recycle it when its lifetime is over. This change alone reduced memory usage of the writer from 90MB to 4.5MB. For the detached buffer of compressed data used by gzfile_write_raw, we can only clear the string (not recycle it) since user code may hold references to it (but the data would be clobbered, anyways). This reduced memory usage slightly by around 0.5MB (because it's smaller compressed data). Combined, these changes reduce the anonymous RSS memory of a dedicated writer process from over 90MB to under 4MB. before: # user system total real writer 7.823332 0.053333 7.876665 ( 7.881464) writer RssAnon: 92944 kB reader 6.969999 0.076666 7.046665 ( 7.906377) reader RssAnon: 109820 kB after: writer 7.359999 0.000000 7.359999 ( 7.360639) writer RssAnon: 4040 kB reader 6.346667 0.070000 6.416667 ( 7.387654) reader RssAnon: 98272 kB Script used: ------- require 'zlib' require 'benchmark' nr = 16384 * 2 def stats(pfx, bm) str = "#{bm}#{File.readlines("/proc/#$$/status").grep(/^RssAnon:/)[0]}" puts str.gsub!(/^/m, pfx) end rd, wr = IO.pipe pid = fork do buf = ((0..255).map(&:chr).join * 128).freeze rd.close gzip = bm = Benchmark.measure do nr.times { gzip.write(buf) } gzip.close wr.close end stats('writer ', bm) end wr.close buf = '' gunzip = n = 0 bm = Benchmark.measure do begin gunzip.readpartial(16384, buf) n += buf.size rescue EOFError break end while true end stats('reader ', bm) Process.waitall ------- * ext/zlib/zlib.c (zstream_discard_input): reuse or recycle hidden input (zstream_reset_input): clear hidden input (zstream_run): detach input and recycle after use (gzfile_write_raw): clear buffer after write [ruby-core:84638] [Feature #14315] git-svn-id: svn+ssh:// b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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