[httperf] reply response time

Arlitt, Martin martin.arlitt at hp.com
Fri Jun 10 01:27:39 PDT 2011


Hi Sylvain

My recommendation is to collect a packet trace, then look at the response and transfer times for individual connections. If you still think there is a problem, then send the trace and the httperf output back to the list. You'll probably want to run a smaller test than the one below though.

Thanks
Martin


> -----Original Message-----
> From: httperf-bounces at linux.hpl.hp.com [mailto:httperf-
> bounces at linux.hpl.hp.com] On Behalf Of Sylvain Geneves
> Sent: Friday, June 10, 2011 1:06 AM
> To: httperf at linux.hpl.hp.com
> Subject: [httperf] reply response time
> 
> Hi,
> 
> I run httperf tests on multiple machines with no apparent problem. The
> throughput seems fine and the server behaves as expected when the rate
> increase.
> But when it comes to analyse response times, I've got a problem : at low rate
> (from 10 to 30) some client nodes httperf show response and transfer times
> below 1msec, like this :
> 
> Reply time [ms]: response 0.1 transfer 0.1
> 
> 
> I run my tests on a cluster over a LAN, where each node have 3 NICS : 2
> ethernet 1Gbps, and 1 Myrinet 10Gbps emulating ethernet.
> All these NICS are connected through switches, so my question is : how is
> that possible ?
> 
> 
> If someone has some insight, I would really appreciate it.
> Best regards,
> Sylvain
> 
> 
> 
> 
> for further details, here is the output of one of the clients :
> 
> 
> Total: connections 9074 requests 66532 replies 66532 test-duration 471.350 s
> 
> Connection rate: 19.3 conn/s (51.9 ms/conn, <=192 concurrent connections)
> Connection time [ms]: min 0.2 avg 8070.0 max 18122.8 median 7721.5 stddev
> 6129.8 Connection time [ms]: connect 0.2 Connection length [replies/conn]:
> 7.332
> 
> Request rate: 141.2 req/s (7.1 ms/req)
> Request size [B]: 104.0
> 
> Reply rate [replies/s]: min 7.6 avg 141.6 max 163.8 stddev 22.9 (94 samples)
> Reply time [ms]: response 0.1 transfer 0.1 Reply size [B]: header 63.0 content
> 14609.0 footer 0.0 (total 14672.0) Reply status: 1xx=0 2xx=66532 3xx=0 4xx=0
> 5xx=0
> 
> CPU time [s]: user 122.56 system 347.76 (user 26.0% system 73.8% total
> 99.8%) Net I/O: 2037.0 KB/s (16.7*10^6 bps)
> 
> Errors: total 0 client-timo 0 socket-timo 0 connrefused 0 connreset 0
> Errors: fd-unavail 0 einval 0 addrunavail 0 ftab-full 0 other 0
> Timeouts: total 0 class0=0 class1=0 class2=0 class3=0 class4=0 class5=0
> class6=0 class7=0 class8=0 class9=0
> 
> Session rate [sess/s]: min 4.20 avg 19.25 max 24.60 stddev 3.17 (9074/9074)
> Session: avg 1.00 connections/session
> Session lifetime [s]: 8.1
> Session failtime [s]: 0.0
> Session length histogram: 0 2676 0 0 0 571 587 625 557 592 606 556 557 585 575
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