(Wow, that was fast)

I have a separate test to measure latency of the instrumentation (just
fetch files with wget). My goal here is to measure throughput and see if
the instrumentation I added to vsFTPd v2.0.5 has an impact on
throughput. I assumed that testing with large files would give me this
kind of measure.

In any case, I'm testing with 512 users and a 10K file. I always get a
report from dkftpbench that 510 (not 512) users are left standing. I see
a report at the end like:

ftp_client_pipe_t::notifyPollEvent_cfd: connect failed, errno 24
robouser509::ftpCmdDone: xerr 24, aborting
ftp_client_pipe_t::shutdown(): m_state 1, cfd 1018, dfd -1, id 509
511 users alive, 1 users dead; at least 20 seconds to end of test
ftp_client_pipe_t::notifyPollEvent_cfd: connect failed, errno 24
robouser511::ftpCmdDone: xerr 24, aborting
ftp_client_pipe_t::shutdown(): m_state 1, cfd 1022, dfd -1, id 511
510 users alive, 2 users dead; at least 20 seconds to end of test

If I test with a 32 byte file I can get dkftpbench to report something
510 users alive, like 100-132 users still alive. But I see that the CPU
and network monitoring utilities report utilization is not at 100%.

From what I understand, dkftpbench stops users that die. e.g. if 100 are
still alive, the remaining 412 will not run again. Is this correct ?
Doesn't this leave the server running at less than 100% load ? Or is
perhaps this necessary because otherwise the server crawls to a halt ?

The server machine is an Intel(R) Xeon(TM) CPU 2.40GHz
that reports 4788.23 bogomips under Linux. The client is a Intel(R)
Pentium(R) M processor 1300MHz that reports 2601.87 bogomips under
Linux.

On Mon, 2009-04-13 at 17:59 -0700, Dan Kegel wrote:
> Hi Kristis,
> the many-low-bandwidth-user case was chosen because it
> is exceptionally stressful for the server. It's still realistic-ish,
> though you might want to also test with few-high-bandwidth-users.
>
> Are you running with a faster client machine than server machine?
>
> It's been a while since I played with ftpbench.
> - Dan
>
> On Mon, Apr 13, 2009 at 5:56 PM, Kristis Makris <kristis.makris@...>
wrote:
> > Hello,
> >
> > I'm trying to understand what are reasonable numbers to use when running
> > dkftpbench.
> >
> > The page says that by default dkftpbench's target bandwidth per client
> > is set at 28.8 kilobits/second. Is this still a reasonable assumption to
> > make today ?
> >
> > I'm running dkftpbench against an ftp server connected through a
> > cross-over cable. The goal is to measure ftp throughput before and after
> > a particular automated instrumentation to the source code. dkftpbench
> > under this configuration always manages to reach the limit of 512
> > Platoon_MAXUSERS, as set in Platoon.h. However, I see through network
> > and CPU monitoring tools that the CPU of the server is not saturated yet
> > under this configuration. Is there an easy way to increase this limit ?
> > Simply raising the value of this variable in the source code to support
> > more users reports segmentation faults of dkftpbench.
> >
> > Looking over other messages in this mailing list I see people reporting
> > generating load in the order of thousands of requests[1]. Is there
> > something I'm missing ?
> >
> > Thanks for any help,
> > Kristis
> >
> > [1] - http://tech.groups.yahoo.com/group/ftpbench/message/278
> >
> >


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