[Zope] Zope performance too low ?

[Michel Pelletier]

> -----Original Message-----
> From: Alexander Staubo [mailto:alex@mop.no]
> Sent: Thursday, June 17, 1999 11:38 AM
> To: Zope Mailing List (E-mail)
> Subject: RE: [Zope] Zope performance too low ?
> 
> 
> I'm not familiar enough to Linux to say this for sure, but my guess is
> that it _would_ be using a high-resolution system timer.
> 

Nope, 'ab' uses gettimeofday(2) to return microseconds, and then does an
internal divide by 1000 to return milliseconds.  This is done all with
itegers however, I suspect there is a loss of precision.

>> Ouch. These extremely low transfer rates bother me. The theoretical
>> bandwidth on a local machine transfer should be way, way
>higher. Otoh,
>> your document was very small, so the stop/start, connect/teardown
>> margins would be relatively high. I'd like to see benchmarks
>> with longer
>> (>3KB) documents.
>>

I redid the same benchmark between two linux boxes on my desk (the same
server as before, the client is RedHat 6.0 on a P166 w/ 10Mb Ethernet
card) with a 36K document, and got 656 KB/sec (~36 requests/sec 147ms
average response time), the effective limit on a moderately loaded
10Mb/s Ethernet lan.  So, Zope can at least hose a 10 Mb Ethernet (Note,
a 70MB FTP between the two machines yielded 800 KB/s, I think the amount
of request/response and tcp connect/disconnect overhead could account
for the other 144 KB/s, at least to a 10% margin of error).

When Rob buys me a 100MB card for my other machine, I'll rerun the
benchmark to see if Zope can beat the 10Mb limit.

Also not that the ~37 requests per second I got (this is the average
between all benchmarks) equates to approx *3.2 million hits per day* on
one moderately fast PII with no fancy hardware.

> Otoh, if transfers really were fast (that is, faster than 
> 10-11KB/sec),
> and the time taken to complete a request was low, the transfer time
> should explode exponentially. (Eg., 10K transferred in 10ms 
> should yield
> a transfer rate 1MB/sec.)

With abitrary precision numbers, yes.  I don't have enough time to
investigate why the number was so low for my initial benchmark.

> 
> I'd be very interested to hear about what the CPU load was during the
> test run. If it's anything above 5-8% (average), that's not 
> promising at
> all. The fact that adding more concurrent sessions did not regrade
> performance seems to indicate that CPU load was not too bad.

Note that load average and % of time spent in the CPU are not the same
thing.  The load average hit 1.5 but that just means the machine was
busy, not swamped.  To test a a vague theory here, I fired up X,
Netscape, vmware (which is a massive CPU hog) and a bunch of shells and
XEmacs, and ran a 10000 request benchmark.  The machine ran smoothly,
vmware didn't stutter or pause, X switched quickly between virtual
screens, and XEmacs didn't even appear to feel it.  Meanwhile Zope
happily pushed 538 Kb/s out the ether card.

> 
> I'm planning on putting together a simple httplib-built benchmark test
> just to get some raw numbers, although I'd like to try putting the
> timing logic inside Zope.
> 

We would be interested in seeing what you come up with (code and
numbers).

-Michel