On 08/10/12 11:08, Quentin Barnes wrote: > On Mon, Oct 8, 2012 at 6:10 AM, Steve Dickson <SteveD@xxxxxxxxxx> wrote: >> On 05/10/12 13:57, Quentin Barnes wrote: > [...] >>> Since for our work, for other reasons, we've switched over to >>> using NFSv3 TCP mounts, so I can't justify spending a lot of time >>> debugging this UDP/RPC problem. However, for example if someone >>> wants me to try something out and gather some new test results or >>> a patch to test, I can squeeze that in. > [...] >> >> I think there probably has been a steady decline in UPD performance >> over the years. > > In my data, after the initial big hit between RHEL4 and RHEL5, > NFSv3/UDP performance went back up peaking with 2.6.31, then declined > with 2.6.32 and RHEL6, and has then held steady ever since. Wow... Impressive... Very rarely do we get a such a time line in WRT performance... I'm not sure what happen in the 2.6.32 kernel, but maybe it has something to do with the RPC slot table??? That pure speculation... > > Now I have seen a significant dip my NFSv3/TCP performance data > after 3.3 with 3.6 (I don't have data points for 3.4 & 3.5), but > didn't want to get into that here and I hadn't looked into it hard > enough yet to verify it. Now this is not good... I do remember come claims that RHEL5 was quicker than RHEL6, but there was never any numbers to back it up... > >> The main reason is that nobody uses it since TCP is a >> much better transport to use with NFS... > > I disagree somewhat, at least for my particular configuration and > networks. With my testing and tuning with FreeBSD and 2.6.9 and > earlier Linux kernels, NFSv3/UDP overall performance is generally > 10%-15% better than NFSv3/TCP. I did meant in production... We too still test v2 over UDP and TCP... > >> Why are you still using UDP as your transport? > > We're not. See my above quoted paragraph. I still measure and > monitor NFSv3/UDP's performance as part of my kernel development > work improving the kernel's NFS performance for our needs, but since > no one uses UDP mounts in house currently, I can't justify the time > to find and fix the bug. Agreed... Justifying working/fixing technology what we are moving away from is tough... steved. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
