Date: Sun, 22 Jul 2012 20:20:06 -0500 From: Adam Vande More <amvandemore@gmail.com> To: Jakub Lach <jakub_lach@mailplus.pl> Cc: freebsd-questions@freebsd.org Subject: Re: "da0: 40.000MB/s transfers" What was rationale behind pegging USB 2.0 at 40MB/s? Message-ID: <CA%2BtpaK22qemQgGLJCy0R9X8poL8W1kcNGyw_ZgH9n9-a8JZmfg@mail.gmail.com> In-Reply-To: <1342998350089-5729042.post@n5.nabble.com> References: <1342992043358-5729028.post@n5.nabble.com> <CA%2BtpaK3qWnh_MUfBAEzTexsJdXu4JP5nPG=z4jJdUUd2qwSUxQ@mail.gmail.com> <1342998350089-5729042.post@n5.nabble.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sun, Jul 22, 2012 at 6:05 PM, Jakub Lach <jakub_lach@mailplus.pl> wrote: > Speaking of misunderstanding, that's certainly > possible. > > How much overhead is "normal" and alternatively, > why in FreeBSD USB 2.0 reports as "40MB/s" and > not other arbitrary number. > The overhead includes many different things including hardware latency. However the big one is USB communication itself. That is static, you can't change it and it doesn't vary(assuming same communication type). Your reported speeds are typical, and in all likelihood would be very similar under another OS. -- Adam Vande More
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CA%2BtpaK22qemQgGLJCy0R9X8poL8W1kcNGyw_ZgH9n9-a8JZmfg>