16 Jun 2024

Compiling latest gcc to test more architectures

Off late, I've had two separate needs to compile GCC by hand and although my first foray into compiling gcc from git took patience, stumbling over the basics was interesting to say the least.

The first time I realised that an old GCC version could matter, was this feedback [1] that one of my buildfarm members was running an old (for its arch) gcc version, something that I almost never paid much attention to. The other being that that led me to newer architectures (more on that below) and how this could repeat itself if / when I end up playing with more architectures.

So finally, I can say I have a framework that frequently checks / recompiles gcc and ensures all my local tests are using the latest and the greatest gcc :) . (I am happy with how this has taken shape on my home server, and once I am able to port it to my other machines, don't see why this shouldn't land on github).

Now admittedly, compiling gcc on a nightly basis was already an overkill, but then what the heck - I went and did this hourly basis just because well-why-not. My personal ask was to:

  1. Incrementally learn how compiling gcc unfolds
  2. Have some fun scripting while at it
  3. ... but most importantly, see whether I could utilize this experience in other experiments where the idea is to forewarn database developers about upcoming changes.

A little more on point 3 above, I oversee a few machines on the postgres buildfarm and they differ in some aspects:

  1. Different archictures:
    1. aarch64: Gravitons
    2. x86-64: A vanilla off-the-shelf dell workstation
    3. armv7l - Raspberry Pi4
  2. Different GCCs:
    1. 8.3.0 (default in pi4)
    2. 7.3.1 (default on most ALs)
    3. 13.2 (default on Ubuntu)
    4. 14.0.1 (naive attempt at compiling whatever cleared make check)
    5. gcc (experimental nightly)
  3. (Internally I also run some different fuzzing workloads but that's besides the point)
  4. (Future plans - add some form of randomizer to test odd combinations of compilation flags, but more on that in an upcoming post)

Now if all goes to plan, I should also add to the mix, 2 new architectures. They wouldn't be the snappiest processors in the market (at least not in the pricing-level I am after), but hey it should be fun to play with!

  1. loongarch64 - (cough) Recent (but sure as butterflies, a promising) entrant - the MIPS64 Loongson has been around for some time now, but my interest has grown off late owing to sporadic reports that its becoming somewhat competitive, which should be interesting to review.
  2. riscv64 - Another interesting arch that should be fun to try out. Again, am not holding my breath that it'd top any charts, but could still end up being interesting nonetheless.

On the GCC front, getting the setup ready and stable, clears the path to now focus upgrading my buildfarm animals one-by-one and basically start focussing beyond this hurdle.

gcseb02 20240615_1700 - git checkout successful.
gcseb02 20240615_1700 - git pull successful.
gcseb02 20240615_1700 - No change in gcc version. Quitting.

gcsa36f 20240615_1800 - git checkout successful.
gcsa36f 20240615_1800 - git pull successful.
gcsa36f 20240615_1800 - gcc has changed - [471fb092601] vs [57af69d56e7]. Recompiling.
gcsa36f 20240615_1800 - make successful
gcsa36f 20240615_1800 - make install successful.
gcsa36f 20240615_1800 - gcc version string has changed from [15.0.0 20240615 (experimental) - 471fb092601] to [15.0.0 20240615 (experimental) - 57af69d56e7]

gcsf66a 20240615_1900 - git checkout successful.
gcsf66a 20240615_1900 - Unable to git pull. Are we connected? Quitting.
gcsf66a 20240615_1900 - git switched back to 57af69d56e7.

gcs629f 20240615_2000 - git checkout successful.
gcs629f 20240615_2000 - git pull successful.
gcs629f 20240615_2000 - gcc has changed - [57af69d56e7] vs [6762d5738b0]. Recompiling.
gcs629f 20240615_2000 - make successful
gcs629f 20240615_2000 - make install successful.
gcs629f 20240615_2000 - gcc version string has changed from [15.0.0 20240615 (experimental) - 57af69d56e7] to [15.0.0 20240615 (experimental) - 6762d5738b0]


gcsc115 20240616_0400 - git checkout successful.
gcsc115 20240616_0400 - git pull successful.
gcsc115 20240616_0400 - No change in gcc version. Quitting.


On-Prem AI chatbot - Hello World!

In continuation of the recent posts... Finally got a on-premise chat-bot running! Once downloaded, the linux box is able to spin up / down t...