Profiling npm install times

4 minute read

When installing Mafalda SFU packets, a problem I’ve suffered several times are install times, specially since I’m using git dependencies. I tried to reduce times by publishing some of the most common packages to npm, so removing need to install and compile development dependencies like Typescript, but still install times were huge for no reason, so I needed some way to measure the install time of each one of the dependencies. This lead out options like UNIX time command or tools like slow-deps, so just by change, I found on StackOverflow a reference to gnomon.

gnomon just only prepend timestamp information to the standard output of another command, so it’s a bit crude for my use case, but with some tweaking can provide the needed info. In this case, by running npm install in verbose mode, we can get detailed info of each one of the steps it follows, so we can measure its time delay. Just only, npm install provides that info in stderr (non sense, what is using stdout for?), so we need to redirect it first so gnomon can get it on its stdin:

npm install --verbose 2>&1 | gnomon

This will show the output in two columns, being the timestamps in the left one. On average, it looks like 90% takes less than 1 second and 99% less than 10 seconds… but there’s a 1% of outliers that get up to 1 minute or more. Focusing on that ones, we find two of them (output is truncated for brevity):

  12.8811s   npm http fetch GET 200 2117ms (cache revalidated)
   0.2557s   npm http fetch GET 200 258ms (cache revalidated)
  59.4045s   npm http fetch GET 200 1325ms (cache revalidated)
   1.1857s   npm info run bcrypt@5.0.1 install node_modules/bcrypt node-pre-gyp install --fallback-to-build

gnomon show the time each line has been the last one shown in the terminal, so that time correspond to the generation of the next line. This is particularly useful when showing “starting…” lines, to know in what task this time has been employed so much, but when showing only the conclusions (like it’s the case), we need to focus on the next line instead.

Total time, 206.7054s, whom 12 are spent on downloading ws package, and a full minute compiling bcrypt instead of using a prebuild image. It’s a bit too much, but since the total time is just a bit over 3 minutes, and the problem is probably due to use Node.js v19.4.0 instead of a LTS version, I would not worry too much.

Another project I have been having more important problems with install time has been the Remote Mediasoup integration tests, where install of all Mafalda SFU subprojects is involved, and in fact Github Actions cancel the job step after about 10-12 minutes (does it has a timeout, or it thinks I’m mining cryptocurrencies?). So checking with gnomon, the timings percentages seems similar, just only we found the outliers got rampage:

  34.4881s   npm verb logfile /home/piranna/.npm/_logs/2023-02-05T11_55_57_787Z-debug-0.log
   0.2060s   npm http fetch GET 200 2345ms (cache revalidated)
  13.4045s   npm http fetch GET 200 1680ms (cache revalidated)
   0.1576s   npm http fetch GET 200 227ms (cache revalidated)
 743.5718s   npm http fetch GET 200 1340ms (cache revalidated)
   0.0409s   npm info run @mafalda/mediasoup@3.11.8 install node_modules/@mafalda/mediasoup node npm-scripts.js install
 188.7822s   npm info run @mafalda/rope-client@0.0.0 postinstall { code: 0, signal: null }
   0.1286s   npm info run mediasoup@3.10.5 postinstall { code: 0, signal: null }

Total time, 1059.6964s (18 minutes), whom of them 34 seconds are spent on downloading Mafalda SFU eslint-config package (hum? Why so much?), and 15 minutes compiling both Mafalda SFU custom Mediasoup prebuilds and the regular one (there are some incompatibilities starting on version 3.10.6 that prevent using the latest one with Mafalda SFU, working on fixing them at this moment).

Mediasoup, what else?

Mediasoup by design is compiled on destination platform at install time, so it can take a lot of time to install with all CPU cores at 100% and the machine totally unresponsive (and I have a laptop with 20 CPU cores…). That’s why I’ve tried in the past and now again to generate and publish automated prebuilds of Mediasoup with a nightly Github Action. I hope to make them work properly with newer versions of the prebuild images.

In any case, my internet connection is not very fast or stable, so it’s not surprising that it takes so long to download all the packages or there are so much differences between them, and results are not conclusive but provides a good guidance. Probably with a better internet connection, it could show the bottleneck is somewhere else, probably at the compilation of packages. In addition to that, a good improvement for gnomon or a similar tool would be to add statistics about CPU load, to see what are the installed packages that put more pressure on the install process.

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