add reading config, add and update docs

docs/config-reference.md

@@ -8,9 +8,12 @@ Note: This primarily uses LibreWolf and Fedora as examples of packages and distr
 ## Top-level config
 
 - `log-level`: Log level `0`-`3` (error, warning, info, or debug)
+  - Default: 1 - warning
 - `max-threads`: The maximum number of threads to be used
   - **See also**: [`threads`](#job-config)
+  - Default is CPU's threads - 2
 - `max-jobs`: The maximum number of jobs to be run at once
+  - Default is 1
 
 **Multithreading notes (IMPORTANT)**: Gregory will first run compilation jobs, then packaging jobs for whatever programs are done, then run the `update-repo` for whichever distros are finished. For this reason, the distro names listed under `packaging` and `update-repo` *must* match.
 
@@ -21,8 +24,8 @@ Note: This primarily uses LibreWolf and Fedora as examples of packages and distr
   - See `--cpus` in the [`podman run` docs](https://docs.podman.io/en/latest/markdown/podman-run.1.html#cpus)
   - *Root may be required for this argument*
   - If not specified, it will fall back to `max-threads`
-- `image`: The Docker image to run the job in
-- `commands`: The commands to run
+- `image`: The Docker image to run the job in *(required)*
+- `commands`: The commands to run *(required)*
   - TODO: Add command file/bash script instead
 - `volumes`: Names of volumes as defined in [`volumes` (top level)](#volumes)
 

docs/default-max-threads.md

@@ -0,0 +1,38 @@
+# Default `max-threads`
+
+The default `max-threads` uses a simple algorithm to get how many threads.
+
+```rs
+if total_threads >= 32 {
+    return total_threads - 4;
+} else if total_threads >= 12 {
+    return total_threads - 2;
+} else if total_threads >= 3 {
+    return total_threads - 1;
+} else {
+    return total_threads;
+}
+```
+
+i.e. with `total_threads` as the number of threads the CPU(s) has:
+
+- If the CPU has 32 or more threads, it will use all but 4 threads
+- If the CPU has 12 or more threads, it will use all but 2 threads
+- If the CPU has 3 or more threads, it will use all but 1 thread
+- Otherwise, i.e. if the CPU has 1 to 2 threads, it will use all threads
+
+---
+
+Alternative algorithms I tried:
+
+```rs
+if total_threads >= 32 {
+    return total_threads - total_threads.div_ceil(10);
+} else if total_threads >= 12 {
+    return total_threads - 2;
+} else if total_threads >= 3 {
+    return total_threads - 1;
+} else {
+    return total_threads;
+}
+```