Ciro Santilli @cirosantilli  40

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JavaScript memory usage benchmark Updated 2026-09-20

In this section we will use the file nodejs/bench_mem.js, tests are run on Node.js v16.14.2 from NVM, Ubuntu 21.10, on Lenovo ThinkPad P51 (2017) which has 32 GB RAM.

First using topp from stackoverflow.com/questions/1221555/retrieve-cpu-usage-and-memory-usage-of-a-single-process-on-linux/40576129#40576129 let's observe the memory usage of some baseline cases.

A C hello world with an infinite loop at the end has:

2.7 MB
770 KB

For a Node.js infinite loop nodejs/infinite_loop.js

topp infinite_loop.js

This gives approximately:

RSS: 20 MB
VSZ: 230 MB

Adding a single hello world to it as in nodejs/infinite_hello.js and running:

topp infinite_hello.js

leads to:

RSS: 26 MB
VSZ: 580 MB

We understand that Node.js preallocates VSZ wildly. No big deal, but it does mean that VSZ is a useless measure for Node.js.

Forcing garbage collection as in nodejs/infinite_hello.js brings it down to 20 MB however:

topp node --expose-gc infinite_hello_gc.js

Finally let's see a baseline for process.memoryUsage nodejs/infinite_memoryusage.js:

node --expose-gc infinite_memoryusage.js

which gives initially:

{
  rss: 23851008,
  heapTotal: 6987776,
  heapUsed: 3674696,
  external: 285296,
  arrayBuffers: 10422
}

but after a few seconds randomly jumps to:

{
  rss: 26005504,
  heapTotal: 9084928,
  heapUsed: 3761240,
  external: 285296,
  arrayBuffers: 10422
}

so we understand that

heapUsed seems constant at 3.7 MB
heapTotal is a very noisy, as it starts at 7 MB, but randomly jumps to 9 MB at one point without apparent reason

Now let's run our main test program.

First a baseline case with an array of length 1:

node --expose-gc bench_mem.js n 1

This gives the same results as node --expose-gc infinite_memoryusage.js. The same result is obtained by doing:

a = undefined

with:

node --expose-gc bench_mem.js dealloc

Not let's vary the size of n a bit with:

node --expose-gc bench_mem.js n N

which gives:

N	`heapUsed`	`heapTotal`	`rss`	`heapUsed` per elem	`rss` per elem
1 M	14 MB	48 MB	56 MB	10	30
10 M	122 MB	157 MB	176 MB	18	15
100 M	906 MB	940 MB	960 MB	9	9.3

"rss per elem" is calculated as: rss - 26 MB, where 26 MB is the baseline RSS seen on n 1.

Similarly "heapUsed per elem" deduces the 4 MB (approximation of the above 3.7 MB) seen on n 1.

Note that to reach MAX_SAFE_INTEGER we would need 8 bytes per elem worst case.

Everything below 100 million (8) is therefore very memory wasteful in terms of RSS.

If we use Int32Array typed array buffers instead of a simple Array:

node --expose-gc bench_mem.js array-buffer n N

we see that the memory is now, unsurprisingly, accounted for under arrayBuffers, e.g. for N 1 million:

{
  rss: 31776768,
  heapTotal: 6463488,
  heapUsed: 3674520,
  external: 4285296,
  arrayBuffers: 4010422
}

Results for different N:

|| N
|| `arrayBuffers`
|| `rss`
|| `rss` per elem

| 1 M
| 4 MB
| 31 MB
| 5

| 10 M
| 40 MB
| 67 MB
| 4.6

| 100 M
| 40 MB
| 427 MB
| 4

We see therefore that typed arrays are much closer to what they advertise (4 bytes per element), even for smaller element counts, as expected.

Now let's try one million objects of type { a: 1, b: -1 }:

node --expose-gc bench_mem.js obj

gives:

{
  rss: 138969088,
  heapTotal: 105246720,
  heapUsed: 70103896,
  external: 285296,
  arrayBuffers: 10422
}

Disaster! Memory usage is up to 70 MB! Why?? We were expecting only about 24, 4 baseline + 2 * 10 for each million int?!

And now an equivalent version using class:

node --expose-gc bench_mem.js class

gives the same result.

Let's try Array:

node --expose-gc bench_mem.js arr

is even worse at 78 MB!! OMG why.

{
  rss: 164597760,
  heapTotal: 129363968,
  heapUsed: 78117008,
  external: 285296,
  arrayBuffers: 10422
}

Let's change the number of fields on the object? First as a sanity check:

node --expose-gc bench_mem.js obj 2

produces as expected the smae result as:

node --expose-gc bench_mem.js obj

so adding properties one by one doesn't change anything from creating the literal all at once. Good.

Now:

node --expose-gc bench_mem.js obj N

gives heapUsed:

1: 70M
2: 70M
3: 70M
4: 70M
5: 110M
6: 110M
7: 110M
8: 134M
9: 134M
10: 134M
11: 158M

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Caenorhabditis elegans Updated 2025-07-16

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www.cell.com/cell-systems/fulltext/S2405-4712(16)30120-X
www.cell.com/cell-systems/fulltext/S2405-4712(16)30151-X A Genome-Scale Database and Reconstruction of Caenorhabditis elegans Metabolism Gebauer, Juliane et al. Cell Systems , Volume 2 , Issue 5 , 312 - 322

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A Three-Dimensional Model of the Myoglobin Molecule Obtained by X-Ray Analysis (1958) Updated 2025-07-16

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www.nature.com/articles/181662a0 on Nature. Paywalled as of 2022.

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Money creation vs tax Updated 2025-07-16

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politics.stackexchange.com/questions/73498/how-is-printing-money-different-from-taxing-people

To Ciro Santilli, a key observation is:

The rich are more easily able to avoid the harm than poor and middle-class people [...] they are more likely to have large amounts of non-cash assets to shield themselves from inflation.

Clearly the rich will be much, much more shielded by keeping large parts of their wealth in shares... from this point of view, it is insane to print money!!! Tax the rich instead...

Mentions:

Erik Finman: twitter.com/erikfinman/status/1446853065320112130

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Geocentric model Updated 2025-07-16

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Copernican heliocentrism Updated 2025-07-16

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SuperTuxKart Updated 2025-07-16

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It is a shame, but this game just doesn't feel good. The controls are just not as snappy as Mario Kart 64, the levels are too wide which limits player interaction, and the weapons feel clumsy weak and unexciting. These are all aspects that the closed source smashkarts.io gets pretty well.

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smashkarts.io Updated 2025-07-16

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smashkarts.io/

Quite good, Ciro Santilli played this a lot in 2021/2022, his user ID: ofo5fNy7wRNC1Cw94YVB4KMOW5f2.

The physics not as good as the original Mario Kart 64, and it is notably missing jump gliding, and generally not as sharp! But it is really not bad.

Some of the weapons were too useless that you are just better firing them straight away at wall immediately to get something better, they could have a little better balancing there. I'm talking about you gatling that takes 10 seconds to finish firing, and does not kill enemies immediately. You are better off just firing that gun immediately when you get it to be able to get another gun ASAP. They seem to have done some balancing there however.

It had no chat option, but in a way it was cool to be forced to communicate non-verbally with people whose usernames you got familiar with. Funny you can love people like that, without ever talking to them. The best way of doing so being tea-bagging by going back and forth on a player after winning.

Performance was sometimes a problem. When Ciro tried it again on December 2022, it was unplayable due to the impossibly large lag. Things were much better again in 2023 however it seems.

Looking for related games:

www.reddit.com/r/IoGames/comments/td1fea/any_games_like_smashkarts_ie_games_with_lobbies/

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Universal wavefunction Updated 2025-07-16

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Dan Jewett Updated 2025-07-16

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MacKenzie Bezos' new husband after she divorced Bezos.

Science teacher at the Lakeside School in Seattle.

www.dailymail.co.uk/femail/article-9338723/Who-billionaire-Mackenzie-Scotts-new-husband-Dan-Jewett.html Who IS billionaire Mackenzie Scott's new husband Dan Jewett?

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Divorce of Jeff and MacKenzie Bezos Updated 2025-07-16

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MacKenzie Bezos went on to marry a science teacher who taught their children.

The contrast with Bezos's girlfriend is simply comical. MacKenzie married the idealistic morally upright science teacher, while Bezos went for a silly sex bomb. Ah, bruta flor, do querer!

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Lost Horse LLC Updated 2025-07-16

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MacKenzie Bezos's charity instrument.

www.irishtimes.com/life-and-style/people/mackenzie-scott-how-the-former-mrs-bezos-became-a-philanthropist-like-no-other-1.4850049 MacKenzie Scott: How the former Mrs Bezos became a philanthropist like no other (2020) has some good mentions:

But as Scott's fame for giving away money has grown, so too has the deluge of appeals for gifts from strangers and old friends alike. That clamour may have driven Scott's already discreet operation further underground, with recent philanthropic announcements akin to sudden lightning bolts for unsuspecting recipients.

The name of the organization is a reference to the old man lost his horse.

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M. mycoides JCVI strain Updated 2025-07-16

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www.newyorker.com/magazine/2022/03/07/a-journey-to-the-center-of-our-cells A Journey to the Center of Our Cells (2022) by James Somers comments on M. genitalium in general, and in particular on the JCVI strains.

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ARTIQ Updated 2025-07-16

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Lattice Microbes Updated 2025-07-16

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GPU accelerated, simulates the Craig's minimized M. genitalium, JCVI-syn3A at a particle basis of some kind.

Lab head is the cutest-looking lady ever: chemistry.illinois.edu/zan, Zaida (Zan) Luthey-Schulten.

2022 paper: www.cell.com/cell/fulltext/S0092-8674(21)01488-4 Fundamental behaviors emerge from simulations of a living minimal cell by Thornburg et al. (2022) published on Cell
faculty.scs.illinois.edu/schulten/lm/ actual source code. No Version control and non-code drop release, openess and best practices haven't reached such far obscure reaches of academia yet. One day.
blogs.nvidia.com/blog/2022/01/20/living-cell-simulation/ Nvidia announcement. That's how they do business, it is quite interesting how they highlight this kind of research.
- catalog.ngc.nvidia.com/orgs/hpc/containers/lattice-microbes has a container

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M. genitalium whole cell model by Covert lab Updated 2025-07-16

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simtk.org/projects/wholecell

www.wholecell.org/

github.com/CovertLab/WholeCell Arghh, MATLAB. github.com/CovertLab/WholeCellSimDB

www.wholecellviz.org/viz.php awesome visualization of simtk, paper: www.ncbi.nlm.nih.gov/pmc/articles/PMC3413483/ A Whole-Cell Computational Model Predicts Phenotype from Genotype - 2013 - Jonathan R. Karr.

Followed up by the E. Coli Whole Cell Model by Covert Lab.

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Market liquidity Updated 2025-07-16

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Lamp Updated 2025-07-16

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Biconvex spherical lens Updated 2025-07-16

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Focal length

Each side is a sphere section. They don't have to have the same radius, they are still simple to understand with different radiuses.

The two things you have to have in mind that this does are:

converges parallel light to a point at center at distance $f$ known as the focal length.
This is for example why you can use lenses to burn things with Sun rays, which are basically parallel.
Conversely, if the input is a point light source at the focal length, it gets converted into parallel light.
image formation: it converges all rays coming from a given source point to a single point image. This amplifies the signal, and forms an image at a plane.
The source image can be far away, and the virtual image can be close to the lens. This is exactly what we need for a camera.
For each distance on one side, it only works for another distance on the other side. So when we set the distance between the lens and the detector, this sets the distance of the source object, i.e. the focus. The equation is:
$\frac{1}{f} = \frac{1}{S _{1}} + \frac{1}{S _{2}}$
(1)
where $S_{1}$ and $S_{2}$ are the two distances.

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Larry Page Updated 2025-07-16

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