sorry to ask some question again, and I am really appreciative of any answers however briefly given. i also must apologized for asking these questions with minimal searching and googling....it is non-trivial to search when u don't know all the keywords....but a oneliner answer to help start the process is much appreciated.
On Fri, Nov 13, 2009 at 8:23 AM, James Carlson <carls...@workingcode.com> wrote: > Peter Teoh wrote: >> Can someone help me understand this? >> >> a. what is the difference between squeue and netstack? > > A netstack instance is allocated for the global zone (and all shared > stack zones), plus one for each exclusive IP stack instance zone. > > When IP stack instances were added, the formerly static storage duration > variables related to networking were moved into the netstack structure. > (A few were left as system-wide globals, but most moved.) > > That's what allows an exclusive IP stack instance zone to have its own > set of IP interfaces. > > The squeue is a synchronization object used by FireEngine. There's > roughly an squeue per CPU and interface on the system. > synchronization in what sense? FIFO sense? ie, a kind of FIFO queue, where packets are stacked and dequeue in the same order it is stacked? > An squeue belongs to exactly one netstack. A netstack may have one or > many squeues. since synchronization is per squeue, therefore there exists an "squeue" lock for each squeue, correct? and since different squeue have their individual lock, it is possible to have concurrent transmission by different squeue at the same time? i suspect no? because if yes, the squeue should be per-interface, or per-hardware network card queue. For those network card with multiqueue, then we can have squeue number to equal the number of queues in the multiqueue NIC. it also puzzle me how this sync-lock is used for. for example, in: http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/cmd/mdb/common/modules/genunix/net.c#1082 Look at all the netstat_xxxxx functions. this is where mdb implement its "::netstat" dcmds, and as it enumerate through the different connection, there is absolutely no locking acquired....is it possible that while reading and printing the information (inside mdb's netstat) the connection gets deleted/dropped, or "dissociated" as mentioned earlier, and continuing access it to print other fields will result in memory corruption? there is also no reference to squeue primitives in the net.c program (above URL). so as netstat enumerate through all the connection (each connection means conn_t primitives), these connection may come from different squeue, correct? > >> generally, >> what is the implication if it is disassociated - can we still pump >> information through the connection? (sorry for talking rubbish.....i >> am really newbie...) > No more data is possible. The user is long gone. We're in clean-up > mode -- the connection will eventually be freed up. > > Disassociating from the netstack means that we no longer need to refer > to the zone that created the connection. > >> b. squeue is per-cpu right? so different cpu will have difference >> squeue? > > Yes. > >> so i supposed there must be a handler function for the >> squeue processing? >> what is the name, and they are different for reading/writing right? > > You'll need to read through the ip_squeue source code, and any > FireEngine documents you can google. It's non-trivial. > >> if they are per-cpu, is there load balancing to rebalance the queue >> when it become imbalanced due to different speed of processing? > > No. > > -- > James Carlson 42.703N 71.076W <carls...@workingcode.com> > -- Regards, Peter Teoh _______________________________________________ networking-discuss mailing list networking-discuss@opensolaris.org
