> Why would you be sending a file to a datagram socket? To send prepacketized video to a DTV headend.
Context: most IPTV deployments deliver video as MPEG-2 Transport Streams over UDP. Digital cable headends are also increasingly IP based. For high-density video on demand you need to send as many streams from a node as possible; the bottleneck is almost always I/O... unless you stream from a Thumper. To make things more interesting, you cannot always send jumbo frames and streams should follow the exact timestamps with a precision on the order of 20-50 msecs or better. The following data is from a x4500 sending about 1.2 Gbps of video streams (about 550 streams in this particular setup) over two interfaces. All of them from different media, and all of them 2 to 4 GB long. Sender processes basically read(), usleep() and send() following a prebuilt index. - That much processor use in kernel space? $ sar -u 3 15:59:05 %usr %sys %wio %idle 16:00:08 2 49 0 49 16:00:11 2 49 0 49 Yes, we are doing a huge lot of syscalls/sec here and a lot of kernel-userspace copying (thus I'd love to try the same with sendfile, as we already do in Linux), see below... $ vmstat 1 kthr memory page disk faults cpu r b w swap free re mf pi po fr de sr m1 m1 m1 m2 in sy cs us sy id 0 0 0 1903944 2118896 0 0 0 0 0 0 0 0 0 0 0 9577 148303 27172 2 55 43 0 0 0 1820744 2035696 0 0 0 0 0 0 0 0 0 0 0 7518 149480 25834 2 50 48 0 0 0 1762504 1977456 0 0 0 0 0 0 0 0 0 0 0 8547 150297 26799 2 53 45 - Is that the Fire Engine being too aggressive at interrupt affinity? (see the number of interrupts per core) $ mpstat 3 CPU minf mjf xcal intr ithr csw icsw migr smtx srw syscl usr sys wt idl 0 0 0 16 1693 300 7250 429 3090 5741 0 40410 2 51 0 47 1 0 0 0 5545 4938 7049 420 3102 5523 0 37647 2 53 0 45 2 0 0 1 890 1 7144 441 2908 4886 0 40037 2 51 0 47 3 0 0 0 695 12 6152 335 2958 4673 0 37630 3 52 0 44 I'd love to hear other suggestions on how to make this beast perform better. Should I get very different results with a recent Nevada snapshot (with the Yosemite patches)? Kindest regards, This message posted from opensolaris.org _______________________________________________ networking-discuss mailing list [email protected]
