Re: IO performance problems in 2.4.19-pre5 when writing to DVD-RAM/ZIP/MO

[Moritz Franosch <jfranosc@physik.tu-muenchen.de>]

> Judging from the performance regression above it would seem the
> new defaults suck rocks.

I first thought that 2.4.19-pre5 would be better than 2.4.18 because
vmstat showed that 2.4.19-pre5 could still read 1-2 MB per second from
HDD while writing to DVD-RAM, whereas 2.4.18 blocked totally for more
than 10 seconds or so. But there are short moments under both kernels
(with default bdflush parameters) where you get data from HDD at a
very high rate before it drops again. It seems the main throughput
over a long time stems from these short moments.


> Can we please stop optimising Linux for a single workload benchmark
> and start tuning it for the common case of running multiple kinds
> of applications and making sure one application can't mess up the
> others ?
> 
> Personally I couldn't care less if my tar went 30% faster if it
> meant having my desktop unresponsive for the whole time.

That's why I did the benchmarks in the first place, because my desktop
was unresponsive while writing to DVD-RAM.


Moritz


-- 
Dipl.-Phys. Moritz Franosch
http://Franosch.org