| commit | 14c7caae5074fdf0d97a3ad995e20c63e4065cbf | [log] [tgz] |
|---|---|---|
| author | Martin Möhrmann <moehrmann@google.com> | Mon Jul 13 18:12:20 2020 +0200 |
| committer | Martin Möhrmann <martisch@uos.de> | Mon Sep 14 19:21:56 2020 +0000 |
| tree | 628b26fe7af8c2be350c88c4c32e2daeb97a9a87 | |
| parent | c0c396bd6ad2aea40f7f302711c8b89e20feb371 [diff] |
runtime: add 24 byte allocation size class
This CL introduces a 24 byte allocation size class which
fits 3 pointers on 64 bit and 6 pointers on 32 bit architectures.
Notably this new size class fits a slice header on 64 bit
architectures exactly while previously a 32 byte size class
would have been used for allocating a slice header on the heap.
The main complexity added with this CL is that heapBitsSetType
needs to handle objects that aren't 16-byte aligned but contain
more than a single pointer on 64-bit architectures.
Due to having a non 16 byte aligned size class on 32 bit a
h.shift of 2 is now possible which means a heap bitmap byte might
only be partially written. Due to this already having been
possible on 64 bit before the heap bitmap code only needed
minor adjustments for 32 bit doublecheck code paths.
Note that this CL changes the slice capacity allocated by append
for slice growth to a target capacity of 17 to 24 bytes.
On 64 bit architectures the capacity of the slice returned by
append([]byte{}, make([]byte, 24)...)) is 32 bytes before and
24 bytes after this CL. Depending on allocation patterns of the
specific Go program this can increase the number of total
alloctions as subsequent appends to the slice can trigger slice
growth earlier than before. On the other side if the slice is
never appended to again above its capacity this will lower heap
usage by 8 bytes.
This CL changes the set of size classes reported in the
runtime.MemStats.BySize array due to it being limited to a
total of 61 size classes. The new 24 byte size class is now
included and the 20480 byte size class is not included anymore.
Fixes #8885
name old time/op new time/op delta
Template 196ms ± 3% 194ms ± 2% ~ (p=0.247 n=10+10)
Unicode 85.6ms ±16% 88.1ms ± 1% ~ (p=0.165 n=10+10)
GoTypes 673ms ± 2% 668ms ± 2% ~ (p=0.258 n=9+9)
Compiler 3.14s ± 6% 3.08s ± 1% ~ (p=0.243 n=10+9)
SSA 6.82s ± 1% 6.76s ± 1% -0.87% (p=0.006 n=9+10)
Flate 128ms ± 7% 127ms ± 3% ~ (p=0.739 n=10+10)
GoParser 154ms ± 3% 153ms ± 4% ~ (p=0.730 n=9+9)
Reflect 404ms ± 1% 412ms ± 4% +1.99% (p=0.022 n=9+10)
Tar 172ms ± 4% 170ms ± 4% ~ (p=0.065 n=10+9)
XML 231ms ± 4% 230ms ± 3% ~ (p=0.912 n=10+10)
LinkCompiler 341ms ± 1% 339ms ± 1% ~ (p=0.243 n=9+10)
ExternalLinkCompiler 1.72s ± 1% 1.72s ± 1% ~ (p=0.661 n=9+10)
LinkWithoutDebugCompiler 221ms ± 2% 221ms ± 2% ~ (p=0.529 n=10+10)
StdCmd 18.4s ± 3% 18.2s ± 1% ~ (p=0.515 n=10+8)
name old user-time/op new user-time/op delta
Template 238ms ± 4% 243ms ± 6% ~ (p=0.661 n=9+10)
Unicode 116ms ± 6% 113ms ± 3% -3.37% (p=0.035 n=9+10)
GoTypes 854ms ± 2% 848ms ± 2% ~ (p=0.604 n=9+10)
Compiler 4.10s ± 1% 4.11s ± 1% ~ (p=0.481 n=8+9)
SSA 9.49s ± 1% 9.41s ± 1% -0.92% (p=0.001 n=9+10)
Flate 149ms ± 6% 151ms ± 7% ~ (p=0.481 n=10+10)
GoParser 189ms ± 2% 190ms ± 2% ~ (p=0.497 n=9+10)
Reflect 511ms ± 2% 508ms ± 2% ~ (p=0.211 n=9+10)
Tar 215ms ± 4% 212ms ± 3% ~ (p=0.105 n=10+10)
XML 288ms ± 2% 288ms ± 2% ~ (p=0.971 n=10+10)
LinkCompiler 559ms ± 4% 557ms ± 1% ~ (p=0.968 n=9+10)
ExternalLinkCompiler 1.78s ± 1% 1.77s ± 1% ~ (p=0.055 n=8+10)
LinkWithoutDebugCompiler 245ms ± 3% 245ms ± 2% ~ (p=0.684 n=10+10)
name old alloc/op new alloc/op delta
Template 34.8MB ± 0% 34.4MB ± 0% -0.95% (p=0.000 n=9+10)
Unicode 28.6MB ± 0% 28.3MB ± 0% -0.95% (p=0.000 n=10+10)
GoTypes 115MB ± 0% 114MB ± 0% -1.02% (p=0.000 n=10+9)
Compiler 554MB ± 0% 549MB ± 0% -0.86% (p=0.000 n=9+10)
SSA 1.28GB ± 0% 1.27GB ± 0% -0.83% (p=0.000 n=10+10)
Flate 21.8MB ± 0% 21.6MB ± 0% -0.87% (p=0.000 n=8+10)
GoParser 26.7MB ± 0% 26.4MB ± 0% -0.97% (p=0.000 n=10+9)
Reflect 75.0MB ± 0% 74.1MB ± 0% -1.18% (p=0.000 n=10+10)
Tar 32.6MB ± 0% 32.3MB ± 0% -0.94% (p=0.000 n=10+7)
XML 41.5MB ± 0% 41.2MB ± 0% -0.90% (p=0.000 n=10+8)
LinkCompiler 105MB ± 0% 104MB ± 0% -0.94% (p=0.000 n=10+10)
ExternalLinkCompiler 153MB ± 0% 152MB ± 0% -0.69% (p=0.000 n=10+10)
LinkWithoutDebugCompiler 63.7MB ± 0% 63.6MB ± 0% -0.13% (p=0.000 n=10+10)
name old allocs/op new allocs/op delta
Template 336k ± 0% 336k ± 0% +0.02% (p=0.002 n=10+10)
Unicode 332k ± 0% 332k ± 0% ~ (p=0.447 n=10+10)
GoTypes 1.16M ± 0% 1.16M ± 0% +0.01% (p=0.001 n=10+10)
Compiler 4.92M ± 0% 4.92M ± 0% +0.01% (p=0.000 n=10+10)
SSA 11.9M ± 0% 11.9M ± 0% +0.02% (p=0.000 n=9+10)
Flate 214k ± 0% 214k ± 0% +0.02% (p=0.032 n=10+8)
GoParser 270k ± 0% 270k ± 0% +0.02% (p=0.004 n=10+9)
Reflect 877k ± 0% 877k ± 0% +0.01% (p=0.000 n=10+10)
Tar 313k ± 0% 313k ± 0% ~ (p=0.075 n=9+10)
XML 387k ± 0% 387k ± 0% +0.02% (p=0.007 n=10+10)
LinkCompiler 455k ± 0% 456k ± 0% +0.08% (p=0.000 n=10+9)
ExternalLinkCompiler 670k ± 0% 671k ± 0% +0.06% (p=0.000 n=10+10)
LinkWithoutDebugCompiler 113k ± 0% 113k ± 0% ~ (p=0.149 n=10+10)
name old maxRSS/op new maxRSS/op delta
Template 34.1M ± 1% 34.1M ± 1% ~ (p=0.853 n=10+10)
Unicode 35.1M ± 1% 34.6M ± 1% -1.43% (p=0.000 n=10+10)
GoTypes 72.8M ± 3% 73.3M ± 2% ~ (p=0.724 n=10+10)
Compiler 288M ± 3% 295M ± 4% ~ (p=0.393 n=10+10)
SSA 630M ± 1% 622M ± 1% -1.18% (p=0.001 n=10+10)
Flate 26.0M ± 1% 26.2M ± 2% ~ (p=0.493 n=10+10)
GoParser 28.6M ± 1% 28.5M ± 2% ~ (p=0.256 n=10+10)
Reflect 55.5M ± 2% 55.4M ± 1% ~ (p=0.436 n=10+10)
Tar 33.0M ± 1% 32.8M ± 2% ~ (p=0.075 n=10+10)
XML 38.7M ± 1% 39.0M ± 1% ~ (p=0.053 n=9+10)
LinkCompiler 164M ± 1% 164M ± 1% -0.27% (p=0.029 n=10+10)
ExternalLinkCompiler 174M ± 0% 173M ± 0% -0.33% (p=0.002 n=9+10)
LinkWithoutDebugCompiler 137M ± 0% 136M ± 2% ~ (p=0.825 n=9+10)
Change-Id: I9ecf2a10024513abef8fbfbe519e44e0b29b6167
Reviewed-on: https://go-review.googlesource.com/c/go/+/242258
Trust: Martin Möhrmann <moehrmann@google.com>
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
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