cmd/compile: reduce allocs to
c85b77c (pre-fmt.go change) levels
Linker and reflect info generation (reflect.go) relies on formatting
of types (tconv). The fmt.Format based approach introduces extra
allocations, which matter in those cases. Resurrected sconv and tconv
code from commit
c85b77c (fmt.go only); and adjusted it slightly.
The formatter-based approach is still used throughout the rest of the
compiler, but reflect.go now uses the tconv method that simply returns
the desired string.
(The timing data below may not be accurate; I've included it only for
comparison with the numbers in issue #16897).
name old time/op new time/op delta
Template 297ms ± 2% 288ms ± 3% -3.12% (p=0.000 n=27+29)
Unicode 155ms ± 5% 150ms ± 5% -3.26% (p=0.000 n=30+30)
GoTypes 1.00s ± 3% 0.95s ± 3% -4.51% (p=0.000 n=28+29)
name old alloc/op new alloc/op delta
Template 46.8MB ± 0% 46.5MB ± 0% -0.65% (p=0.000 n=28+30)
Unicode 37.9MB ± 0% 37.8MB ± 0% -0.24% (p=0.000 n=29+30)
GoTypes 144MB ± 0% 143MB ± 0% -0.68% (p=0.000 n=30+30)
name old allocs/op new allocs/op delta
Template 469k ± 0% 446k ± 0% -5.01% (p=0.000 n=29+30)
Unicode 375k ± 0% 369k ± 0% -1.62% (p=0.000 n=30+28)
GoTypes 1.47M ± 0% 1.37M ± 0% -6.29% (p=0.000 n=30+30)
The code for sconv/tconv in fmt.go now closely match the code from
c85b77c
again; except that the functions are now methods. Removing the use of
the bytes.Buffer in tconv and special-caseing interface{} has helped a
small amount as well:
name old time/op new time/op delta
Template 299ms ± 3% 288ms ± 3% -3.83% (p=0.000 n=29+29)
Unicode 156ms ± 5% 150ms ± 5% -3.56% (p=0.000 n=30+30)
GoTypes 960ms ± 2% 954ms ± 3% -0.58% (p=0.037 n=26+29)
name old alloc/op new alloc/op delta
Template 46.6MB ± 0% 46.5MB ± 0% -0.22% (p=0.000 n=30+30)
Unicode 37.8MB ± 0% 37.8MB ± 0% ~ (p=0.075 n=30+30)
GoTypes 143MB ± 0% 143MB ± 0% -0.31% (p=0.000 n=30+30)
name old allocs/op new allocs/op delta
Template 447k ± 0% 446k ± 0% -0.28% (p=0.000 n=30+30)
Unicode 369k ± 0% 369k ± 0% -0.03% (p=0.032 n=30+28)
GoTypes 1.38M ± 0% 1.37M ± 0% -0.35% (p=0.000 n=29+30)
Comparison between
c85b77c and now (see issue #16897):
name old time/op new time/op delta
Template 307ms ± 4% 288ms ± 3% -6.24% (p=0.000 n=29+29)
Unicode 164ms ± 4% 150ms ± 5% -8.20% (p=0.000 n=30+30)
GoTypes 1.01s ± 3% 0.95s ± 3% -5.72% (p=0.000 n=30+29)
name old alloc/op new alloc/op delta
Template 46.8MB ± 0% 46.5MB ± 0% -0.66% (p=0.000 n=29+30)
Unicode 37.8MB ± 0% 37.8MB ± 0% -0.13% (p=0.000 n=30+30)
GoTypes 143MB ± 0% 143MB ± 0% -0.11% (p=0.000 n=30+30)
name old allocs/op new allocs/op delta
Template 444k ± 0% 446k ± 0% +0.48% (p=0.000 n=30+30)
Unicode 369k ± 0% 369k ± 0% +0.09% (p=0.000 n=30+28)
GoTypes 1.35M ± 0% 1.37M ± 0% +1.47% (p=0.000 n=30+30)
There's still a small increase (< 1.5%) for GoTypes but pending a complete
rewrite of fmt.go, this seems ok again.
Fixes #16897.
Change-Id: I7e0e56cd1b9f981252eded917f5752259d402354
Reviewed-on: https://go-review.googlesource.com/29087
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>