On Wed, Mar 30, 2011 at 08:36:45PM +0200, Walter Haidinger wrote: > Am 30.03.2011 15:23, schrieb Claudio Jeker: > > Buffers below 8k are stupid. For TCP just use 32k or even 64k. 512byte > > buffers are silly. They get internally rounded up since the smallest > > packet seems to be 512bytes data plus header. This will give you TCP send > > and recv buffers of around 1200bytes. No wonder it is slow as hell. > > Throughput isn't the issue. The system gets unusable with sizes < 2048. > The machine freezes, it takes a couple of seconds for the next shell > prompt to appear, like under really heavy load (I'd say way >30). > > Of course bufsizes that small make no sense and your patch eliminates > the lock ups, but the they show there is still some bug. I'd expect slow > nfs transfers but not the behavior as if under heavy load. (*)
NFS is a strange beast and I guess running with to small buffers results in such side effects. This has nothing todo with the buffer scaling but more with the way NFS works. > This is just to let to know, maybe you want to have a further look. I'm not interested. Maybe someone else likes to dig deep into NFS. I guess there is a reason why the default is 8k. > Why did I test with small buffer sizes too? Well, I got another email > which said about the mount options, obviously regarding the buffer sizes: > > "When you jackfuck that knob with other values, what is the result? > Troubleshooting isn't only for others, son!" > > A reminder that this is an OpenBSD list... ;-) > Luckily I always make sure to have my asbestos on when dealing with! -- :wq Claudio
