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Buffer speedups #1048

Merged
merged 2 commits into from
Mar 5, 2015
Merged

Buffer speedups #1048

merged 2 commits into from
Mar 5, 2015

Commits on Mar 5, 2015

  1. lib: hand-optimize Buffer constructor 

    The Buffer constructor is used pervasively throughout io.js, yet it was
one of the most unwieldy functions in core.  This commit breaks up the
constructor into several small functions in a way that makes V8 happy.

About 8-10% CPU time was attributed to the constructor function before
in buffer-heavy benchmarks.  That pretty much drops to zero now because
V8 can now easily inline it at the call site.  It shortens the running
time of the following simple benchmark by about 15%:

    for (var i = 0; i < 25e6; ++i) new Buffer(1);

And about 8% from this benchmark:

    for (var i = 0; i < 1e7; ++i) new Buffer('x', 'ucs2');

PR-URL: nodejs#1048
Reviewed-By: Trevor Norris <[email protected]>
    @bnoordhuis
    bnoordhuis committed Mar 5, 2015
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  2. lib: avoid .toLowerCase() call in Buffer#write() 

    Avoid a costly String#toLowerCase() call in Buffer#write() in the
common case, i.e., that the string is already lowercase.  Reduces
the running time of the following benchmark by about 40%:

    for (var b = Buffer(1), i = 0; i < 25e6; ++i) b.write('x', 'ucs2');

PR-URL: nodejs#1048
Reviewed-By: Trevor Norris <[email protected]>
    @bnoordhuis
    bnoordhuis committed Mar 5, 2015
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