On Fri, Aug 26, 2011 at 12:25, Yehuda Sadeh Weinraub <yehud...@gmail.com> wrote: > On Fri, Aug 26, 2011 at 12:10 PM, Tommi Virtanen > <tommi.virta...@dreamhost.com> wrote: >> e.g. 8kB at a time. And at that point you might as well just use read >> and not read_iterate, that'll do the memsetting etc for you, and then >> you can use a static buffer and avoid malloc/free every round. There's >> no shortcut to be had from "skipping" holes when you need to feed >> bytes to a hash function. > > Well, when using read_iterate you avoid reading extra data over the > network when the object (chunk) exists (and is sparse). We can > probably have some optimization here, and only allocate and memset a > buffer once for the case where len == objsize and reuse it later.
Reading src/librbd.cc, I don't see the holes going over the wire in either case. read() is just a simple wrapper on top of read_iterate(), that memsets to 0 in case of a hole. Which in this case he was doing manually, so why not just use read() in the first place. -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
