Essentially, dpkg is hilariously slow due to its approach in issuing fsync calls for every file - eatmydata wrapper injects a shared library which turns that into a no-op.
I haven't timed it rigorously, but I experienced up to 10x speedup in container builds by just wrapping dpkg with eatmydata.
I’m not the OP, but in an example I just tried it took build-essential from 48s to 39s (timed on the third step, without and then with the call to eatmydata):
from debian:sid
run apt update && env DEBIAN_FRONTEND=noninteractive apt-get install --yes eatmydata
run apt update && eatmydata env DEBIAN_FRONTEND=noninteractive apt-get install --yes build-essential
I ran it three more times. Plain install was 50s 48s 47s; eatmydata was 46s 46s 46s.
Installing build-essential probably does enough non-dpkg IO to account for the difference (install scripts etc, for example when libc changes and the system scans for running daemons) but it isn’t much and the delta may well be statistically insignificant.
- Docker image: `debian:stable-slim`
- `docker system prune -a` ran before each test.
- Packages installed: `build-essential ca-certificates libssl-dev software-properties-common wget curl git`
Results:
Default Debian settings: 48.32 seconds
force-unsafe-io enabled: 55.86 seconds
eatMyData enabled: 35.04 seconds
Most of the reason I switched from Ubuntu -> Arch is that working with alpine allowed me to realize that installing packages and their dependencies don't have to take so long.