[httperf] A strange output

John Talbot jtalbot at proionta.gr
Fri Mar 30 05:52:24 PST 2007


Indeed. The session file is a single small-ish file repeated 20 times.

I did some more test immediately after this output, and found that the 
server resets the connection after every 2 successful requests (given 
that all these requests are asking for the same file/URL).
Furthermore the output I pasted was not reproducible. All subsequent 
tests produced exactly 9 connresets for every session, as expected, and 
all sessions were successful in the histogram.

But the question is this: why didn't httperf, in this particular httperf 
run that I pasted, retry sessions that had connresets until it either 
got a different error (like client-timo) or a successful session? What 
could be the reasons that caused that? Wouldn't that be httperf's 
expected behaviour? [Or does, for example, httperf quit a session when a 
connreset occurs before the first request in a session?]

Thanks
- John


Arlitt, Martin wrote:
>
> Hi John
>
>  
>
> Without more details of your test session and your test environment it 
> is difficult to know exactly what the cause of the problem is. 
>  However, it appears that for some subset of requests, the server is 
> resetting the connections.  In some cases this happens before httperf 
> has sent a request on the connection, and in some cases afterwards.  I 
> suggest spending some time to determine why the server is resetting 
> these connections; given the small number of concurrent connections 
> you are using, I find this behavior a bit surprising.
>
>  
>
> Martin
>
>  
>
> ------------------------------------------------------------------------
>
> *From:* httperf-bounces at napali.hpl.hp.com 
> [mailto:httperf-bounces at napali.hpl.hp.com] *On Behalf Of *John Talbot
> *Sent:* Thursday, March 29, 2007 6:41 PM
> *To:* httperf at napali.hpl.hp.com
> *Subject:* [httperf] A strange output
>
>  
>
> I got the following weird output on an httperf run I did:
>
> It's completely mystifying what might have produced this output - is 
> it a problem on the target server, a problem on the host running 
> httperf, or both?
>
> What seems strange to me about it is that it appears that httperf 
> doesn't retry the connections which were "connreset" here (my until 
> now experience with httperf has been that reset connections were 
> retried and resulted in either a successful sessions or in some other 
> type of error).
>
> But here all the errors are connreset - could someone please enlighten 
> me as to what might be going on?
>
> Thanks in advance,
> - John
>
> ------------------------------------------------------------------------
>
>
> httperf --timeout=5 --client=0/1 --server=myserver --port=80 --uri=/ 
> --max-connections=2 --max-piped-calls=25 --rate=1 --send-buffer=4096 
> --recv-buffer=16384 --wsesslog=120,0.000,/urls-list
> Maximum connect burst length: 1
>
> Total: connections 268 requests 1066 replies 840 test-duration 119.116 s
>
> Connection rate: 2.2 conn/s (444.5 ms/conn, <=2 concurrent connections)
> Connection time [ms]: min 5.3 avg 25.3 max 91.9 median 16.5 stddev 17.9
> Connection time [ms]: connect 2.3
> Connection length [replies/conn]: 4.421
>
> Request rate: 8.9 req/s (111.7 ms/req)
> Request size [B]: 105.0
>
> Reply rate [replies/s]: min 0.0 avg 6.4 max 20.0 stddev 9.3 (23 samples)
> Reply time [ms]: response 3.3 transfer 0.0
> Reply size [B]: header 387.0 content 54.0 footer 0.0 (total 441.0)
> Reply status: 1xx=0 2xx=840 3xx=0 4xx=0 5xx=0
>
> CPU time [s]: user 88.62 system 29.72 (user 74.4% system 25.0% total 
> 99.3%)
> Net I/O: 4.0 KB/s (0.0*10^6 bps)
>
> *Errors: total 226 client-timo 0 socket-timo 0 connrefused 0 connreset 
> 226 **
> Errors: fd-unavail 0 addrunavail 0 ftab-full 0 other 0
> *
> Session rate [sess/s]: min 0.00 avg 0.35 max 1.00 stddev 0.47 (42/120)
> Session: avg 4.52 connections/session
> Session lifetime [s]: 0.1
> Session failtime [s]: 0.0
> Session length histogram: 78 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 42
>

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