> That includes overheads from whatever file system / raid layers > you have on top of the device. Please do the dd straight to > /dev/sdd or /dev/sdd1. > > Also, I note that while you have an Intel 845 chipset, your kernel > doesn't mention either the local APIC or the I/O APIC. I would have > expected both to be present; using them typically results in less > IRQ sharing and lower IRQ handling overheads. Might be worthwhile > to try to enable them. > > /Mikael I think I've figured out what's the problem. Measuring directly from device performance increased up to 13MB/s. After enabling APIC & I/O APIC it was up to 18MB/s. I tried to yank all other controllers but it didn't have any effect. This ruled out pretty much everything except the Promise TX4 .. and the HDD itself. I tried to plug disk into motherboard controller (HPT374) and it gives me exactly same write performance ... 18MB/s. Apparently this brand new 1 Tt Western Digital is either amazingly slow on write or I have faulty unit. Model number: WDC WD1000FYPS-01ZKB0 Model name: Western Digital RE2-GP (Green Power) Western Digitals Specification for the drive state: Transfer Rate (Buffer To Disk) 84 MB/s (Sustained) Uh, I'm a little puzzled .. what to do next .. I don't think I want to have drive with real world 5-10MB/s write performance .. replacing it trough warranty may be troublesome since it works fine otherwise. Perhaps I'll contact WD directly ... It would seem to be as always, problems is where you least expect it to be. -- Marko Koivusalo -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
