Gary Buhrmaster gary.buhrmaster@gmail.com writes:
On Mon, Jul 18, 2022 at 6:44 AM Petr Lautrbach plautrba@redhat.com wrote:
Dan Čermák dan.cermak@cgc-instruments.de writes:
Just out of curiosity, how large is the speedup typically?
It depends on the number of threads your machine has. But you could get some data for comparison using `fixfiles -T 1 restore` and `fixfiles -T 0 restore` on a running system. The following times are reported on my workstation:
Has anyone run such a test on a system using classic ("spinning rust") HDDs? It is sometimes the case that parallelizing activities that are I/O intensive can result in excessive seek activity that can result in rather elongated elapsed times (much worse than single threaded operation).
We have only one machine with a rotary HDD and 4 threads:
# for T in 1 0 4; do chcon -R -t root_t /etc/bad-label/; sync; for i in $(seq 1 3); do echo $i > /proc/sys/vm/drop_caches; done; echo -T $T; time fixfiles -F -T $T restore; done
-T 1 real 3m32,046s user 2m0,068s sys 0m24,005s
-T 0 real 2m32,859s user 2m9,265s sys 0m26,775s
-T 4 real 2m38,355s user 2m9,695s sys 0m27,042s
Petr