> > > Tread tag fid offset count > > > > > > Rread tag count data > > > > without having the benefit of reading ken's thoughts ... > > > > you can have 1 fd being read by 2 procs at the same time. > > the only way to do this is by having multiple outstanding tags. > > > I thought the tag was assigned by the client, not the server (since it shows > up as a field in the T message), and that this meant it's possible for one > client to put many of it's own locally tagged requests into the server, and > wait for them in any order it chooses.
that's what i thought i said. (from the perspective of pread and pwrite not (T R)^(read write).) > > i think the complaint about 9p boils down to ordering. > > if i want to do something like > > cd /sys/src/9/pc/ ; cat sdata.c > > that's a bunch of walks and then an open and then a read. > > these are done serially, and each one takes 1rtt. > > > > Some higher operations probably require an ordering. But there's no reason > you could do two different sequences of walks, and a read concurrently is > there? not that i can think of. but that addresses throughput, but not latency. - erik
