Interrupt performance

[Slawa Olhovchenkov]

On Tue, Feb 01, 2011 at 02:23:32PM +0200, Stefan Lambrev wrote:

> >> Also in the past ENOBUF was not handled properly in linux.
> >> 
> >> http://wiki.freebsd.org/AvoidingLinuxisms - Do not rely on Linux-specific socket behaviour. In particular, default socket buffer sizes are different (call setsockopt() with SO_SNDBUF and SO_RCVBUF), and while Linux's send() blocks when the socket buffer is full, FreeBSD's will fail and set ENOBUFS in errno.
> > 
> > Yes, about ENOBUFS with udp socket I told.
> > And this behaviour (block on udp socket send) in Solaris too.
> > I don't know what behaviour is right.
> 
> Well, according to the man pages in linux and fbsd the bsd behavior is right. I was looking into this long time ago with some red hat linux.

I have't any idea for blocking UDP socket, other then benchmarks.

Now I test TCP and see strange result.

# netperf -H 10.200.0.1 -t TCP_STREAM -C -c -l 60 -- -s 128K -S 128K
TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.200.0.1 (10.200.0.1) port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % U      % U      us/KB   us/KB

131072 131072 131072    60.00       522.08   -1.00    -1.00    0.000   -0.314

Now I run ./loop 2000000000 and see stoping transmit.

 procs      memory      page                   disk   faults         cpu
 r b w     avm    fre   flt  re  pi  po    fr  sr ad0   in   sy   cs us sy id
 2 0 0    107M   435M     0   0   0   0     0   0   0 15939  618 39502  0 77 23
 1 0 0    107M   435M     0   0   0   0     0   0   0 15904  619 39355  0 75 25
 1 0 0    107M   435M     0   0   0   0     0   0   0 16193  615 40085  0 79 21
 1 0 0    107M   435M     0   0   0   0     0   0   0 16028  623 39708  1 74 26
 1 0 0    107M   435M     0   0   0   0     0   0   0 15965  615 39475  0 77 23
 1 0 0    107M   435M     0   0   0   0     0   0   0 16012  636 39666  0 84 16 <-- run ./loop 2000000000
 2 0 0    109M   435M    46   0   0   0     9   0   0 9632  507 24041 48 51  1
 2 0 0    109M   435M     0   0   0   0     0   0   0 6592  319 16419 73 27  0
 2 0 0    109M   435M     0   0   0   0     0   0   0  455  136 1250 100 0  0
 2 0 0    109M   435M     0   0   0   0     0   0   0  420  127 1170 99  1  0
 2 0 0    109M   435M     0   0   0   0     0   0   0  395  127 1127 100 0  0
 2 0 0    109M   435M     0   0   0   0     0   0   0  428  127 1209 100 0  0
 2 0 0    109M   435M     0   0   0   0     0   0   0  537  130 1434 99  1  0
 2 0 0    109M   435M     0   0   0   0     0   0   0  449  136 1255 100 0  0
 1 0 0    107M   435M    14   0   0   0    37   0   0 7634  400 19044 56 30 14  <- end ./loop (Elapsed 8470990 us)
 1 0 0    107M   435M     0   0   0   0     0   0   0 14893  579 37088  0 75 25
 1 0 0    107M   435M     0   0   0   0     0   0   0 16123  615 40163  0 78 22
 1 0 0    107M   435M     0   0   0   0     0   0   0 15220  582 37939  0 72 28

Wtf?