diff options
author | normal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2018-01-05 20:48:55 +0000 |
---|---|---|
committer | normal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2018-01-05 20:48:55 +0000 |
commit | a55abcc0ca6f628fc05304f81e5a044d65ab4a68 (patch) | |
tree | 9b0f3d3bb2f81c3797f666dd4cc25535a3f8fdc2 /ext/zlib | |
parent | fb7ed3b32f82d807c5a6232d8c90ed56b4739739 (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 = Zlib::GzipWriter.new(wr)
bm = Benchmark.measure do
nr.times { gzip.write(buf) }
gzip.close
wr.close
end
stats('writer ', bm)
end
wr.close
buf = ''
gunzip = Zlib::GzipReader.new(rd)
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://ci.ruby-lang.org/ruby/trunk@61631 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'ext/zlib')
-rw-r--r-- | ext/zlib/zlib.c | 58 |
1 files changed, 47 insertions, 11 deletions
diff --git a/ext/zlib/zlib.c b/ext/zlib/zlib.c index 7906e0fba3..ea3531df96 100644 --- a/ext/zlib/zlib.c +++ b/ext/zlib/zlib.c @@ -845,19 +845,50 @@ zstream_append_input(struct zstream *z, const Bytef *src, long len) static void zstream_discard_input(struct zstream *z, long len) { - if (NIL_P(z->input) || RSTRING_LEN(z->input) <= len) { - z->input = Qnil; + if (NIL_P(z->input)) { } - else { - z->input = rb_str_substr(z->input, len, - RSTRING_LEN(z->input) - len); + else if (RBASIC_CLASS(z->input) == 0) { + /* hidden, we created z->input and have complete control */ + char *ptr; + long oldlen, newlen; + + RSTRING_GETMEM(z->input, ptr, oldlen); + newlen = oldlen - len; + if (newlen > 0) { + memmove(ptr, ptr + len, newlen); + } + if (newlen < 0) { + newlen = 0; + } + rb_str_resize(z->input, newlen); + if (newlen == 0) { + rb_gc_force_recycle(z->input); + z->input = Qnil; + } + else { + rb_str_set_len(z->input, newlen); + } + } + else { /* do not mangle user-provided data */ + if (RSTRING_LEN(z->input) <= len) { + z->input = Qnil; + } + else { + z->input = rb_str_substr(z->input, len, + RSTRING_LEN(z->input) - len); + } } } static void zstream_reset_input(struct zstream *z) { - z->input = Qnil; + if (!NIL_P(z->input) && RBASIC_CLASS(z->input) == 0) { + rb_str_resize(z->input, 0); + } + else { + z->input = Qnil; + } } static void @@ -994,7 +1025,7 @@ zstream_run(struct zstream *z, Bytef *src, long len, int flush) { struct zstream_run_args args; int err; - VALUE guard = Qnil; + VALUE old_input = Qnil; args.z = z; args.flush = flush; @@ -1008,12 +1039,13 @@ zstream_run(struct zstream *z, Bytef *src, long len, int flush) } else { zstream_append_input(z, src, len); - z->stream.next_in = (Bytef*)RSTRING_PTR(z->input); - z->stream.avail_in = MAX_UINT(RSTRING_LEN(z->input)); /* keep reference to `z->input' so as not to be garbage collected after zstream_reset_input() and prevent `z->stream.next_in' from dangling. */ - guard = z->input; + old_input = zstream_detach_input(z); + rb_obj_hide(old_input); /* for GVL release and later recycle */ + z->stream.next_in = (Bytef*)RSTRING_PTR(old_input); + z->stream.avail_in = MAX_UINT(RSTRING_LEN(old_input)); } if (z->stream.avail_out == 0) { @@ -1051,7 +1083,10 @@ loop: if (z->stream.avail_in > 0) { zstream_append_input(z, z->stream.next_in, z->stream.avail_in); - RB_GC_GUARD(guard); /* prevent tail call to make guard effective */ + } + if (!NIL_P(old_input)) { + rb_str_resize(old_input, 0); + rb_gc_force_recycle(old_input); } if (args.jump_state) @@ -2330,6 +2365,7 @@ gzfile_write_raw(struct gzfile *gz) str = zstream_detach_buffer(&gz->z); OBJ_TAINT(str); /* for safe */ rb_funcall(gz->io, id_write, 1, str); + rb_str_resize(str, 0); if ((gz->z.flags & GZFILE_FLAG_SYNC) && rb_respond_to(gz->io, id_flush)) rb_funcall(gz->io, id_flush, 0); |