Posted: Thu Apr 15, 2010 11:43 Post subject: Broadcom diy usb 1.0/2.0 speed tests
So I modded my bcm5352 and the speeds are better than the mmc sdhc driver floating around, but still pretty slow for usb. This is on the usb 2.0 channel with a run of the mill flash drive.
Code:
root@fscd@#$g54t:~# hdparm -tT /dev/scsi/host0/bus0/target0/lun0/disc
Timing cached reads: 116 MB in 2.00 seconds = 58.00 MB/sec
Timing buffered disk reads: 4 MB in 4.70 seconds = 871.49 kB/sec
Can anyone else confirm? Please post your benchmark results
I guess what I was really looking for was the discrepancy between the speed of the flash memory and usb in the buffered read test, i.e.
"-T
Perform timings of cache reads for benchmark and comparison purposes. For meaningful results, this operation should be repeated 2-3 times on an otherwise inactive system (no other active processes) with at least a couple of megabytes of free memory. This displays the speed of reading directly from the Linux buffer cache without disk access. This measurement is essentially an indication of the throughput of the processor, cache, and memory of the system under test. If the -t flag is also specified, then a correction factor based on the outcome of -T will be incorporated into the result reported for the -t operation. "
The usb works fine, but I guess I just wanted to know where the bottleneck is, and how to improve upon it if possible. I am limited by a 5v adapter's 8.75 watt limit rather than using a regulator, which is more than ample output for the router and a couple spec draw usb devices, but am unable to overclock with the stability I once had prior to the usb mod (when a device is connected). I will underclock to see how much it affects that number I am fixated on understanding.
edit: it no longer likes either overclocking or underclocking when the usb is plugged
Code:
hub.c: new USB device 00:03.0-2, assigned address 4
usb.c: USB device not accepting new address=4 (error=-71)
hub.c: new USB device 00:03.0-2, assigned address 5
usb.c: USB device not accepting new address=5 (error=-145)
hub.c: new USB device 00:03.0-2, assigned address 6
usb.c: USB device not accepting new address=6 (error=-71)
hub.c: new USB device 00:03.0-2, assigned address 7
usb.c: USB device not accepting new address=7 (error=-145)
hub.c: new USB device 00:03.0-2, assigned address 8
usb.c: USB device not accepting new address=8 (error=-145)
hub.c: new USB device 00:03.0-2, assigned address 9
usb.c: USB device not accepting new address=9 (error=-145)
hub.c: new USB device 00:03.0-2, assigned address 10
usb.c: USB device not accepting new address=10 (error=-145)
hub.c: new USB device 00:03.0-2, assigned address 11
usb.c: USB device not accepting new address=11 (error=-145)