stream: some simplification

[ronag]

~7% improvement

NOTE: Contains 2 commits to reduce the number of PRs.

streams/writable-manywrites.jscallback='no'writev='no'sync='no'n=20000006.27%±6.47%±8.63%±11.26%streams/writable-manywrites.jscallback='no'writev='no'sync='yes'n=2000000*8.43%±6.68%±8.90%±11.59%streams/writable-manywrites.jscallback='no'writev='yes'sync='no'n=20000007.77%±7.88%±10.49%±13.69%streams/writable-manywrites.jscallback='no'writev='yes'sync='yes'n=2000000*6.79%±5.75%±7.65%±9.96%streams/writable-manywrites.jscallback='yes'writev='no'sync='no'n=2000000***11.31%±6.08%±8.11%±10.60%streams/writable-manywrites.jscallback='yes'writev='no'sync='yes'n=2000000**7.76%±5.46%±7.27%±9.46%streams/writable-manywrites.jscallback='yes'writev='yes'sync='no'n=20000006.12%±7.40%±9.85%±12.82%streams/writable-manywrites.jscallback='yes'writev='yes'sync='yes'n=2000000**8.11%±4.90%±6.52%±8.48%

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/30806/

[ronag]

This condition is a duplicate of what's inside of clearBuffer. However, it is here on purpose since clearBuffer is not inlineable.

[mscdex]

This seems to have a negative effect on Duplex creation:

streams/creation.js kind='duplex' n=50000000 *** -6.94 % ±3.44% ±4.62% ±6.09% 

[ronag]

@mscdex Flaky made?

Local:

 streams/creation.js kind='duplex' n=5000000 2.88 % ±5.44% ±7.25% ±9.46% 

[ronag]

Benchmark CI (creation): https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/556/

[ronag]

Nope, seems consistent:

17:55:08streams/creation.jskind='duplex'n=50000000***-7.40%±2.49%±3.31%±4.31%

Strange... not sure how this PR could cause that

[ronag]

https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/557/

[ronag]

@mscdex: I'm quite baffled why this PR would affect duplex creation performance. Any ideas?

Anyway, a 7% performance increase in writing I guess is still worth it with a 7% performance degradation in creation?

[mscdex]

I don't know offhand, you'd probably have to compare either the generated/optimized code or optimizer/inliner trace output before and after this PR to see what is different.