[httperf] Concurrent connections

Arlitt, Martin martin.arlitt at hp.com
Tue Dec 13 09:09:18 PST 2011


Thanks for the confirmation.

Martin


From: Kurien Mathew [mailto:kurienmatheww at gmail.com]
Sent: Tuesday, December 13, 2011 8:54 AM
To: Arlitt, Martin
Subject: Re: [httperf] Concurrent connections

Hi Martin,

I confirm that the packet capture shows the desired number of connections.

Thanks
Kurien

On Tue, Dec 13, 2011 at 4:08 PM, Arlitt, Martin <martin.arlitt at hp.com<mailto:martin.arlitt at hp.com>> wrote:
Hi Kurien

There are plausible explanations for this. One is that some of the connections have completed before others have been established.(the minimum connection time in your second test was 110ms).  At the same time, some of the TCP connections may not have been established immediately (e.g., httperf client sends a TCP SYN, but the server is busy and delays sending the SYN ACK). If you want to understand exactly what is happening, my suggestion is to collect a packet trace while running your experiment, then look at the lifecycle of each connection (e.g., when the SYN was sent, when the SYN ACK was received, when the 10 requests were sent & replies received, etc). If you've compiled httperf in debug mode, you may also be able to gather the information using an appropriate debug level (I usually use packet traces myself).

Martin


From: httperf-bounces at linux.hpl.hp.com<mailto:httperf-bounces at linux.hpl.hp.com> [mailto:httperf-bounces at linux.hpl.hp.com<mailto:httperf-bounces at linux.hpl.hp.com>] On Behalf Of Kurien Mathew
Sent: Tuesday, December 13, 2011 6:20 AM
To: httperf at linux.hpl.hp.com<mailto:httperf at linux.hpl.hp.com>
Subject: [httperf] Concurrent connections

Hello,

I notice that the actual number of concurrent connections is variable & lower that the number requested. For eg below are two sample runs where the number of concurrent connections is lower than the requested 516. Am I missing something from my command? How can one ensure that number of concurrent connections are always as desired?

Kurien

[user at halom perf]$ httperf -v 4 --hog --timeout 2.0 --burst-length 1 --num-calls 10 --num-conns 516 --rate=516 --server 192.168.99.200 --uri /ck375000.ts
httperf --verbose --hog --timeout=2 --client=0/1 --server=192.168.99.200 --port=80 --uri=/ck375000.ts --rate=516 --send-buffer=4096 --recv-buffer=16384 --num-conns=516 --num-calls=10
httperf: warning: open file limit 4800 > 1024 FD_SETSIZE; limiting max. # of open files to FD_SETSIZE
httperf: maximum number of open descriptors = 1024
Maximum connect burst length: 3

Total: connections 516 requests 5160 replies 5160 test-duration 2.617 s

Connection rate: 197.2 conn/s (5.1 ms/conn, <=432 concurrent connections)
Connection time [ms]: min 180.2 avg 1475.9 max 2153.0 median 1643.5 stddev 472.1
Connection time [ms]: connect 2.2
Connection length [replies/conn]: 10.000

Request rate: 1971.9 req/s (0.5 ms/req)
Request size [B]: 78.0

Reply rate [replies/s]: min 0.0 avg 0.0 max 0.0 stddev 0.0 (0 samples)
Reply time [ms]: response 37.4 transfer 110.0
Reply size [B]: header 234.0 content 375000.0 footer 0.0 (total 375234.0)
Reply status: 1xx=0 2xx=5160 3xx=0 4xx=0 5xx=0

CPU time [s]: user 0.18 system 2.43 (user 7.0% system 92.7% total 99.7%)
Net I/O: 722743.4 KB/s (5920.7*10^6 bps)

Errors: total 0 client-timo 0 socket-timo 0 connrefused 0 connreset 0
Errors: fd-unavail 0 addrunavail 0 ftab-full 0 other 0


[user at halom perf]$ httperf -v 4 --hog --timeout 2.0 --burst-length 1 --num-calls 10 --num-conns 516 --rate=516 --server 192.168.99.200 --uri /ck375000.ts
httperf --verbose --hog --timeout=2 --client=0/1 --server=192.168.99.200 --port=80 --uri=/ck375000.ts --rate=516 --send-buffer=4096 --recv-buffer=16384 --num-conns=516 --num-calls=10
httperf: warning: open file limit 4800 > 1024 FD_SETSIZE; limiting max. # of open files to FD_SETSIZE
httperf: maximum number of open descriptors = 1024
Maximum connect burst length: 2

Total: connections 516 requests 5160 replies 5160 test-duration 2.422 s

Connection rate: 213.1 conn/s (4.7 ms/conn, <=399 concurrent connections)
Connection time [ms]: min 110.0 avg 1333.5 max 1946.2 median 1532.5 stddev 494.2
Connection time [ms]: connect 1.4
Connection length [replies/conn]: 10.000

Request rate: 2130.8 req/s (0.5 ms/req)
Request size [B]: 78.0

Reply rate [replies/s]: min 0.0 avg 0.0 max 0.0 stddev 0.0 (0 samples)
Reply time [ms]: response 32.6 transfer 100.7
Reply size [B]: header 234.0 content 375000.0 footer 0.0 (total 375234.0)
Reply status: 1xx=0 2xx=5160 3xx=0 4xx=0 5xx=0

CPU time [s]: user 0.14 system 2.28 (user 5.8% system 94.2% total 100.0%)
Net I/O: 780965.0 KB/s (6397.7*10^6 bps)

Errors: total 0 client-timo 0 socket-timo 0 connrefused 0 connreset 0
Errors: fd-unavail 0 addrunavail 0 ftab-full 0 other 0
[user at halom perf]$


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