Marco Flohrer has posted an inquiry to de.comp.os.unix.linux.hardware
[German] <slrnae8q66.go4.marco.flohrer@diamond.csn.tu-chemnitz.de> that his
Seagate 36ES2 was slow with a DawiControl 2976UW (SYM53C875), only
around 25 MB/s. I have the same observation with a Fujitsu MAH3182MP
with an Adaptec 2940UW Pro which is not much faster. Either bus has an
active LVD/SE terminator.
Single-user mode,
time dd if=/dev/XXX of=/dev/null bs=65536 count=10240
(671,1 MB) linear read.
Table shows throughput in decimal MB/s (M = 1,000,000)
2.5 2.4 FBSD max.
UWSCSI Fuj MAH3182MP 7200/min 32,1 29,4 35,1 TQ 40
UDMA66 Max 4W060H4 5400/min 27,1 26,7 25,7 66
UDMA66 IBM DTLA307045 7200/min 37,2 37,5 37,2 TQ 2.5 66
UDMA66 WDC AC420400D 5400/min 15,5 15,5 15,5 TQ 2.5 66
--------------
table is in decimal MB/s.
2.4: Linux 2.4.19-pre2-ac3
2.5: Linux 2.5.15
FBSD: FreeBSD 4.6-RC (Tagged Queueing Broken)
The IDE drives are attached to a VIA 82C686 (KT133), the Fujitsu
(actually an U-160 drive) to the mentioned Adaptec.
FBSD gets about 20% better throughput. It's far from perfect, but 90% of
the maximum is probably almost as good as we can get.
Why is Linux SCSI so slow?
-- Matthias Andree - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/