Previously whenever a BinaryWriter was created it immediately created a
128 kb Uint8List. When compiling analysis server et al (all sources used
to compile the analysis server) this results in allocating ~2.7GB (with
`takeBytes` returning a total of <54MB in this case).
This CL reduces this buffer to 5KB instead, reducing the overhead on GC.
With a 5KB buffer (about 94% `takeBytes` calls return less than 5KB)
we instead allocate about 130MB in this case.
It being mostly a GC pressure change (and that it will change up when
GC happens) benchmarking it isn't great, nevertheless this is what I
got:
Analyzing CFE et al (without dart2wasm stuff):
```
msec task-clock:u: -1.9193% +/- 0.5797% (-166.76 +/- 50.37) (8688.58 -> 8521.82)
page-faults:u: -7.8067% +/- 0.0517% (-12297.80 +/- 81.48) (157529.64 -> 145231.84)
cycles:u: -1.6454% +/- 0.6021% (-600019148.06 +/- 219543431.36) (36465937621.72 -> 35865918473.66)
instructions:u: -1.1447% +/- 0.4261% (-498854632.50 +/- 185671028.34) (43579529159.92 -> 43080674527.42)
branch-misses:u: -2.8986% +/- 1.9360% (-4171049.68 +/- 2785886.58) (143898017.08 -> 139726967.40)
seconds time elapsed: -1.9201% +/- 0.5796% (-0.17 +/- 0.05) (8.69 -> 8.53)
seconds user: -1.7259% +/- 0.6256% (-0.14 +/- 0.05) (8.37 -> 8.23)
seconds sys: -7.0216% +/- 4.0546% (-0.02 +/- 0.01) (0.32 -> 0.29)
Comparing GC data:
Scavenge( new space) goes from 176 to 138
MarkSweep( old space) goes from 1 to 2
Evacuate(store buffer) goes from 1 to 0
Notice combined GC time goes from 2811 ms to 2959 ms (notice only 1 run each).
```
Analysis server et al:
```
msec task-clock:u: -2.6522% +/- 0.5847% (-467.52 +/- 103.07) (17627.23 -> 17159.71)
page-faults:u: -3.5245% +/- 0.0502% (-10456.22 +/- 148.92) (296669.38 -> 286213.16)
cycles:u: -2.5953% +/- 0.5919% (-1921850003.72 +/- 438308899.83) (74050606844.82 -> 72128756841.10)
instructions:u: -1.8325% +/- 0.0006% (-1578705053.84 +/- 483572.09) (86149571116.38 -> 84570866062.54)
branch-misses:u: -4.0379% +/- 2.0070% (-12275829.02 +/- 6101639.40) (304013449.34 -> 291737620.32)
seconds time elapsed: -2.6510% +/- 0.5845% (-0.47 +/- 0.10) (17.64 -> 17.17)
seconds user: -2.5518% +/- 0.6162% (-0.43 +/- 0.10) (17.00 -> 16.56)
seconds sys: -5.3499% +/- 2.5859% (-0.03 +/- 0.02) (0.63 -> 0.60)
Comparing GC data:
Scavenge( new space) goes from 363 to 273
MarkSweep( promotion) goes from 21 to 20
Evacuate(store buffer) goes from 1 to 0
Notice combined GC time goes from 5415 ms to 5542 ms (notice only 1 run each).
```
Change-Id: I78b1a9a1c882ad486eff97b3aee1ed5f29235891
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/458560
Commit-Queue: Jens Johansen <jensj@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Jens Johansen
9481e3615c