hi: 2011/8/2 Felipe Balbi <balbi@xxxxxx>: > Hi, > > (please break your lines at 80 characters ;-) > > On Mon, Aug 01, 2011 at 02:57:42PM -0700, Perry Wagle wrote: >> If I have a 2.6.31.6 kernel running on an ARM, what kind of >> performance can I get how? I'm getting about 14 MB/sec read and write > > it pretty much depends on the controller you're using and how optimized > the driver for that controller is. This is really a case-by-case > analysis. While the stack itself poses some overhead, I would say > (didn't measure ok ;-) Linux's USB stacks (host and device side) are > quite low overhead... > >> and the customer of my customer (I'm an independent contractor) is >> expecting 20-30. Is that possible in linux? (I get the same > > well, if the HW _can_ do better and the SW isn't optimized, then yes, > why not ?!? > >> performance on a x86_64 running ubuntu 10.10). What's the deal we can >> tell them? > > we can't really tell you how to talk to your customers, what we can tell > is that without further information on the setup (which controller, > which device, who's playing the role as Host and who's playing role as > Device, which chipset on Host side, which disk are you using, etc) it's > quite difficult to give any tips. > per my experience. the performance will depend on following factors: 1. the speed of your device, since different device will adopt different algorithm to handle read/write. 2. the controller, as Felipe mentioned. For example, different controller will adopt different memory bus for read/write, ddr2 or ddr3. 3. how busy is your arm system. Isn't it possible to get the max read/write speed from your device provider? -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
