Bugzilla

On a 16-core M3 MBP, my clobber build times are:

9m 29s with `--disable-optimize`: https://share.firefox.dev/414j6sV
6m 37s with `--enable-optimize=O1`: https://share.firefox.dev/3Rn50Qf

`--disable-optimize` causing this 50% increase in build times seems to be down to host tools being affected by `--disable-optimize`, as pointed out by Mike in bug 1867594 comment 7.

Looking at our build telemetry, it looks like about 70%-80% of developer builds use `--disable-optimize`, that number being over 80% on macOS:
https://sql.telemetry.mozilla.org/queries/96326/source?p_date=d_last_30_days#237829

I guess the usage is probably so high for historical reasons, since `--disable-optimize --disable-debug` has in the past been recommended for faster build times while still generating a reasonably fast Firefox build.

But now that we have vendored in so many host tools, and until this bug is fixed, `--disable-optimize` is probably something to avoid when possible. Particularly on Apple silicon.

On a 16-core M3 MBP, my clobber build times are:

9m 29s with `--disable-optimize`: https://share.firefox.dev/414j6sV
6m 37s with `--enable-optimize="-O1"`: https://share.firefox.dev/3Rn50Qf

`--disable-optimize` causing this 50% increase in build times seems to be down to host tools being affected by `--disable-optimize`, as pointed out by Mike in bug 1867594 comment 7.

Looking at our build telemetry, it looks like about 70%-80% of developer builds use `--disable-optimize`, that number being over 80% on macOS:
https://sql.telemetry.mozilla.org/queries/96326/source?p_date=d_last_30_days#237829

I guess the usage is probably so high for historical reasons, since `--disable-optimize --disable-debug` has in the past been recommended for faster build times while still generating a reasonably fast Firefox build.

But now that we have vendored in so many host tools, and until this bug is fixed, `--disable-optimize` is probably something to avoid when possible. Particularly on Apple silicon.