Remarks about the benchmark
Posted Nov 27, 2012 17:38 UTC (Tue) by man_ls
In reply to: Remarks about the benchmark
Parent article: Langasek: Upstart in Debian
Proportions are meaningless since both start systems are doing a number of discrete tasks, not a continuous sequence. When Upstart went from 35 to 23 seconds it was a huge advantage; now that systemd uses just one less second, it is immaterial in practice.
Anyway, if they were using an SSD or ramdisk, those timings are still horrible, since boot ought to be instantaneous.
Really? Let us do some quick math: SATA III
achieves 600 MB/sec. If your userspace is 1 GB (not unheard of), then it will take about two seconds just to load all that information from disk into memory. This is besides any hardware initialization tasks, computations and so on. I think that 2.5 seconds in real life is an impressive achievement, even for a modest userspace. It will never be "instantaneous" even with the fastest SSD money can buy, at least until SATA VII or so (just joking, at that point userspace will probably be about 8 GB). But for my particular needs we are well beyond the point of diminishing returns.
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