mbuffer does two things in this example. First it makes sure that pktcdvd always has data to write. Second is that it feeds this data in 4k chunks (reblocking).
These results from the dd approach are consistant with my earlier testing:
stingray ~ # dd if=/dev/zero of=/dev/hdc bs=32768 count=25000 25000+0 records in 25000+0 records out 819200000 bytes (819 MB) copied, 92.2253 seconds, 8.9 MB/s
stingray ~ # dd if=/dev/zero of=/dev/hdc bs=32769 count=25000 2643+0 records in 2643+0 records out 86608467 bytes (87 MB) copied, 223.764 seconds, 387 kB/s
stingray ~ # pktsetup dvdrw /dev/hdc stingray ~ # dd if=/dev/zero of=/dev/pktcdvd/dvdrw bs=32768 count=25000 25000+0 records in 25000+0 records out 819200000 bytes (819 MB) copied, 86.3305 seconds, 9.5 MB/s
stingray ~ # dd if=/dev/zero of=/dev/pktcdvd/dvdrw bs=32769 count=25000 25000+0 records in 25000+0 records out 819225000 bytes (819 MB) copied, 1312.45 seconds, 624 kB/s
Basically this tells me that pktcdvd does no or inefficient merging of incoming data (at least in my case). Or pktcdvd is slowed down for a different (internal) reason.
For the slow performance cases I see a initial peak of good write speed This is ovious buffer followed by "noisy" and slow write speeds. When buffer starts to being written onto disc and you need to still readig folders or compare files, or even write too small files you'll got low
El Martes, 12 de Diciembre de 2006 17:26, Johannes Niess escribió: performance as well.
What other data do you need to diagnose this strange problem?
Thank you very much fot your help!
Johannes Nieß
-- Gustavo Guillermo Pérez Compunauta uLinux www.compunauta.com -- To unsubscribe, e-mail: packet-writing+unsubscribe@opensuse.org For additional commands, e-mail: packet-writing+help@opensuse.org