performance: Blob.text and Blob.arraybuffer are 10x+ slower on 20.x

The blob/blob.js benchmark is taking hours: https://ci.nodejs.org/view/Node.js benchmark/job/benchmark-node-micro-benchmarks/1402/console

This probably didn’t take so long in the past, there is this PR that changed the Blob’s behavior a lot: https://github.com/nodejs/node/pull/45258/

From what I saw, the problem is in the JS->C++ transitions, for each piece of data it crosses JS->C++.

Furthermore, the text function expects arraybuffer and then calls decode, when we could just decode the data as soon as we get it from the C++ instead of keeping everything in memory and then discarding it.

I can do some optimizations on the JS side but I think this could be largely improved if we do the heavy operations on C++, I have no idea how to handle the asynchronous code on C++, so I accept some hints or if anyone wants to try work on this.

About this issue

Original URL
State: open
Created 9 months ago
Comments: 15 (15 by maintainers)

Commits related to this issue

src: introduce PullAll method to speed up blob.text/arrayBuffer Refs: https://github.com/nodejs/performance/issues/118 — committed to debadree25/node by debadree25 9 months ago
src: introduce PullAll method to speed up blob.text/arrayBuffer Refs: https://github.com/nodejs/performance/issues/118 — committed to debadree25/node by debadree25 3 months ago

Most upvoted comments

This will be a tricky one as the new mechanism underlying the C++ implementation of Blob is also going to be used for the QUIC implementation that I’m currently working on. It also serves as the underlying bit for file-backed Blob. There is lots of room for performance improvement here but I would appreciate this not being changed right at this moment as it could lead to conflicts with the ongoing QUIC implementation work. What would probably be the most valuable right now would be just identifying where the key bottlenecks – identifying those so that we can circle back around to making those pieces faster.

jasnell on Sep 22, 2023

Some benchmark data:

NodeJS 16.20.1

name	ops/sec	samples
text (128)	17,269	57
text (1024)	10,257	57
arrayBuffer (128)	24,974	53
arrayBuffer (1024)	10,955	57
slice (0, 64)	48,310	67
slice (0, 512)	23,750	66

NodeJS 18.17.0

name	ops/sec	samples
text (128)	36,176	74
text (1024)	13,691	69
arrayBuffer (128)	36,788	74
arrayBuffer (1024)	14,305	75
slice (0, 64)	49,139	71
slice (0, 512)	26,774	76

NodeJS 20.5.0

name	ops/sec	samples
text (128)	3,194	74
text (1024)	380	76
arrayBuffer (128)	3,478	80
arrayBuffer (1024)	407	75
slice (0, 64)	45,076	66
slice (0, 512)	16,484	64

H4ad on Sep 21, 2023

just stuck on how to make the pulling part async similar to how we are doing queueMicrotask in js in cpp, Is there maybe some sort of way to queue jobs in c++ part

Pretty sure you were looking for v8::Isolate::EnqueueMicrotask

joyeecheung on Sep 26, 2023

so I kinda did git bisect and I suspect it was either created by:

https://github.com/nodejs/node/pull/47320

or created by those:

rluvaton on Sep 26, 2023