[ntp:questions] Using Trimble TSIP under Linux

Rick Jones rick.jones2 at hp.com
Mon Oct 29 23:59:03 UTC 2012


Kennedy, Paul <P.Kennedy at fugro.com.au> wrote:
> I heard a rumour the ethernet port on the pi is serviced as part of the
> USB port, and has a 1 millisecond interrupt interval.  I tried to read
> up on this, and did see something to that effect, but it is still very
> vague to me.

It may be that the pi's CPU hasn't the "oomph" to get > 1000
transactions per second on such a test anyway, but perhaps you could
try a netperf TCP_RR test to the pi and see what transaction rate it
reports.

Just be certain to have the same rev of netperf on both sides (the pi
and the load generator), start netserver on the pi (./netserver) and
initiate the test from the load generator:

netperf -H <pi> -l 30 -t TCP_RR -v 2

if you ./configure --enable-histogram when you build netperf on the
load generator, it will then give you a histogram of the individual
RTTs:

$ src/netperf -H raj-8510w -t TCP_RR -v 2
MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to raj-8510w.local () port 0 AF_INET : histogram : demo : first burst 0
Local /Remote
Socket Size   Request  Resp.   Elapsed  Trans.
Send   Recv   Size     Size    Time     Rate         
bytes  Bytes  bytes    bytes   secs.    per sec   

16384  87380  1        1       10.00    9473.34   
16384  87380 
Alignment      Offset         RoundTrip  Trans    Throughput
Local  Remote  Local  Remote  Latency    Rate     10^6bits/s
Send   Recv    Send   Recv    usec/Tran  per sec  Outbound   Inbound
    8      0       0      0   105.559   9473.336 0.076     0.076 

Histogram of request/response times
UNIT_USEC     :    0:    0:    0:    0:    0:    0:    0:    0:    0:    0
TEN_USEC      :    0:    0:    0:    0:    0:    0:    0:    0: 4827: 73601
HUNDRED_USEC  :    0: 15124: 1095:   47:   12:    7:    4:    4:    1:    2
UNIT_MSEC     :    0:    6:    1:    1:    1:    1:    1:    0:    0:    0
TEN_MSEC      :    0:    0:    0:    0:    0:    0:    0:    0:    0:    0
HUNDRED_MSEC  :    0:    0:    0:    0:    0:    0:    0:    0:    0:    0
UNIT_SEC      :    0:    0:    0:    0:    0:    0:    0:    0:    0:    0
TEN_SEC       :    0:    0:    0:    0:    0:    0:    0:    0:    0:    0
>100_SECS: 0
HIST_TOTAL:      94735

You can use omni output selection to get the various percentiles
directly:

$ src/netperf -H raj-8510w -t TCP_RR -- -o rt_latency,min_latency,max_latency,p50_latency,p90_latency,p99_latency,mean_latency,stddev_latency
MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to raj-8510w.local () port 0 AF_INET : histogram : demo : first burst 0
Round Trip Latency usec/tran,Minimum Latency Microseconds,Maximum Latency Microseconds,50th Percentile Latency Microseconds,90th Percentile Latency Microseconds,99th Percentile Latency Microseconds,Mean Latency Microseconds,Stddev Latency Microseconds
105.483,82,8103,97,135,205,105.16,58.10

rick jones
-- 
the road to hell is paved with business decisions...
these opinions are mine, all mine; HP might not want them anyway... :)
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