Date: Thu, 5 Oct 2006 19:56:50 +0200 From: Ulrich Spoerlein <uspoerlein@gmail.com> To: Hans Petter Selasky <hselasky@c2i.net>, freebsd-usb@freebsd.org Subject: Re: New UMASS driver available for testing Message-ID: <20061005175650.GA1342@roadrunner.q.local> In-Reply-To: <20061003171548.GA1325@roadrunner.q.local> References: <200609171214.49165.hselasky@c2i.net> <20060930152928.GB1441@roadrunner.q.local> <200610010944.04652.hselasky@c2i.net> <20061003171548.GA1325@roadrunner.q.local>
next in thread | previous in thread | raw e-mail | index | archive | help
Ulrich Spoerlein wrote: > 258998272 bytes transferred in 1771.034516 secs (146241 bytes/sec) > dd if=/dev/da0 of=/dev/zero bs=$i 0.20s user 3.10s system 0% cpu 29:31.05 total > 258998272 bytes transferred in 775.213552 secs (334099 bytes/sec) > dd if=/dev/da0 of=/dev/zero bs=$i 0.01s user 0.41s system 0% cpu 12:55.23 total > 258998272 bytes transferred in 650.920062 secs (397896 bytes/sec) > dd if=/dev/da0 of=/dev/zero bs=$i 0.00s user 0.07s system 0% cpu 10:50.93 total > 258998272 bytes transferred in 641.615133 secs (403666 bytes/sec) > dd if=/dev/da0 of=/dev/zero bs=$i 0.00s user 0.03s system 0% cpu 10:41.63 total > 258998272 bytes transferred in 641.612930 secs (403667 bytes/sec) > dd if=/dev/da0 of=/dev/zero bs=$i 0.00s user 0.04s system 0% cpu 10:41.63 total I tested the same USB stick on a Gentoo/Linux machine, though it is roughly twice as fast as my own machine: Linux DVPC03 2.6.17-gentoo-r4 #1 SMP PREEMPT Mon Aug 14 17:19:40 CEST 2006 i686 Intel(R) Celeron(R) CPU 3.06GHz GNU/Linux Oct 5 11:19:45 localhost usb 4-2: new full speed USB device using ohci_hcd and address 2 Oct 5 11:19:45 localhost usb 4-2: configuration #1 chosen from 1 choice Oct 5 11:19:45 localhost scsi4 : SCSI emulation for USB Mass Storage devices Oct 5 11:19:45 localhost usb-storage: device found at 2 Oct 5 11:19:45 localhost usb-storage: waiting for device to settle before scanning Oct 5 11:19:50 localhost Vendor: Model: MP3 Flash Stick Rev: 1.00 Oct 5 11:19:50 localhost Type: Direct-Access ANSI SCSI revision: 00 Oct 5 11:19:50 localhost SCSI device sda: 505856 512-byte hdwr sectors (259 MB) Oct 5 11:19:50 localhost sda: Write Protect is off Oct 5 11:19:50 localhost sda: Mode Sense: 20 00 00 00 Oct 5 11:19:50 localhost sda: assuming drive cache: write through Oct 5 11:19:50 localhost SCSI device sda: 505856 512-byte hdwr sectors (259 MB) Oct 5 11:19:50 localhost sda: Write Protect is off Oct 5 11:19:50 localhost sda: Mode Sense: 20 00 00 00 Oct 5 11:19:50 localhost sda: assuming drive cache: write through Oct 5 11:19:50 localhost sda: Oct 5 11:19:50 localhost sd 4:0:0:0: Attached scsi removable disk sda Oct 5 11:19:50 localhost usb-storage: device scan complete Oct 5 11:19:50 localhost scsi.agent[2225]: disk at /devices/pci0000:00/0000:00:03.2/usb4/4-2/4-2:1.0/host4/target4:0:0/4:0:0:0 for i in 512 2k 32k 256k 2048k; do time dd if=/dev/sda of=/dev/null bs=$i;done 258998272 bytes (259 MB) copied, 648.34 seconds, 399 kB/s dd if=/dev/sda of=/dev/null bs=$i 0.14s user 0.84s system 0% cpu 10:48.35 total 258998272 bytes (259 MB) copied, 648.347 seconds, 399 kB/s dd if=/dev/sda of=/dev/null bs=$i 0.04s user 0.65s system 0% cpu 10:48.35 total 258998272 bytes (259 MB) copied, 648.452 seconds, 399 kB/s dd if=/dev/sda of=/dev/null bs=$i 0.02s user 0.65s system 0% cpu 10:48.46 total 258998272 bytes (259 MB) copied, 647.917 seconds, 400 kB/s dd if=/dev/sda of=/dev/null bs=$i 0.00s user 0.74s system 0% cpu 10:47.92 total 258998272 bytes (259 MB) copied, 648.605 seconds, 399 kB/s dd if=/dev/sda of=/dev/null bs=$i 0.00s user 0.78s system 0% cpu 10:48.75 total So, the 400kB/s limit is entirely due to the crappy hardware. I wonder though, why is Linux able to achieve 400kB/s with 512 bytes reads? Is it cheating here? Ulrich Spoerlein -- A: Yes. >Q: Are you sure? > >A: Because it reverses the logical flow of conversation. > >>Q: Why is top posting frowned upon?
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20061005175650.GA1342>