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| author | filipe oliveira <filipecosta.90@gmail.com> | 2022-10-15 10:17:41 +0100 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2022-10-15 12:17:41 +0300 |
| commit | 29380ff77d5da51d3065b810a9f93171f8724c1a (patch) | |
| tree | d40fb96981280f3dd5ddea2833997cfc88d28b35 /.gitignore | |
| parent | 9ab873d9d35e789a228c5281d57c9c4fdc1e4ce1 (diff) | |
| download | redis-29380ff77d5da51d3065b810a9f93171f8724c1a.tar.gz | |
optimizing d2string() and addReplyDouble() with grisu2: double to string conversion based on Florian Loitsch's Grisu-algorithm (#10587)
All commands / use cases that heavily rely on double to a string representation conversion,
(e.g. meaning take a double-precision floating-point number like 1.5 and return a string like "1.5" ),
could benefit from a performance boost by swapping snprintf(buf,len,"%.17g",value) by the
equivalent [fpconv_dtoa](https://github.com/night-shift/fpconv) or any other algorithm that ensures
100% coverage of conversion.
This is a well-studied topic and Projects like MongoDB. RedPanda, PyTorch leverage libraries
( fmtlib ) that use the optimized double to string conversion underneath.
The positive impact can be substantial. This PR uses the grisu2 approach ( grisu explained on
https://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf section 5 ).
test suite changes:
Despite being compatible, in some cases it produces a different result from printf, and some tests
had to be adjusted.
one case is that `%.17g` (which means %e or %f which ever is shorter), chose to use `5000000000`
instead of 5e+9, which sounds like a bug?
In other cases, we changed TCL to compare numbers instead of strings to ignore minor rounding
issues (`expr 0.8 == 0.79999999999999999`)
Diffstat (limited to '.gitignore')
| -rw-r--r-- | .gitignore | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore index e03c834d0..5ed94f1da 100644 --- a/.gitignore +++ b/.gitignore @@ -29,6 +29,7 @@ deps/lua/src/lua deps/lua/src/luac deps/lua/src/liblua.a deps/hdr_histogram/libhdrhistogram.a +deps/fpconv/libfpconv.a tests/tls/* .make-* .prerequisites |