Mark Carroll <m...@ixod.org> writes: > I am trying out NetBSD 8.0 (GENERIC) on an Intel Broadwell NUC5i3RYK > with USB3 ports on the front and back and finding them surprisingly slow > with an external USB3 HDD. dmesg reports, > usbdevs -d -v reports, > > addr 0: super speed, self powered, config 1, xHCI Root Hub(0x0000), vendor > 8086(0x8086), rev 1.00(0x0100) > uhub0 > port 1 addr 1: super speed, power 224 mA, config 1, Elements 25A2(0x25a2), > Western Digital(0x1058), rev 10.19(0x1019), serial 57584D3141353733345A415A > umass0 > > I don't see anything that makes me worry that I won't get USB3 speeds > but,
Agreed; I think you are reading this correctly. > # time dd if=/dev/sd0 of=/dev/null bs=1m count=1k > 1024+0 records in > 1024+0 records out > 1073741824 bytes transferred in 393.518 secs (2728571 bytes/sec) > 399.26 real 0.00 user 1.22 sys > > is rather slower than I had hoped (<3Mb/s reads?): at that speed it'll > take a long time to cover the 2TB of the disk! You are using the block device, not the raw device. This traditionally mattered on Unix and I think it might not on modern Linux. Use /dev/rsd0d instead. I am hopeful that this is your only problem. > I also tried a USB3 Seagate drive, > port 1 addr 5: super speed, power 224 mA, config 1, Expansion(0x231a), > Seagate(0x0bc2), rev 7.06(0x0706), serial NA829NLT > and got around the same data read rate. > > From the internal SSD it gets 58684036 bytes/sec so at least the problem > seems limited to USB, ahcisata seems fine. That seems slow. I get (adding space ot make it readable) 258 111 015 bytes/s rsd0d 68 900 271 bytes/s sd0d on a machine that's from 2010, with a decent but not exotic SSD. Also, I recently tried out a USB3 samsung external SSD (again, not exotic - just basic decent stuff). I got around 100 MB/s, which is not really fast, but way better than USB2. But, I got mysterious read errors about 100GB into the drive when reading back. On USB2, it works fine. But, this is some maybe-sketchy USB3 add-on card that came with my hand-me-down PC from a friend, that I have never used before. >> xhci driver is at best experimental. I'm not sure that's really true in 8.