Disable IIS5 asp buffering good idea ?

We've an asp application, which also uses some COM+ objects to access an SQL
Server 2000 backend server.

Our clients are all connecting thru phone dial-up lines, so they have "slow"
lines. Some of the "transactions" could return something like 500Kb - 1000Kb
formated html data to the client. The asp buffering is enabled on the IIS 5
server.

During those "heavy transactions", I observe that two DLLHOST processes
consume all available cpu in the IIS server, cpu which is split equally 50%
to each process. I've tracked that one of the process is serving the asp
pages, and the other is hosting the COM+ objects. The issolation level of
the IIS application is "medium".

One of those "heavy transactions" can take as long as 30 seconds to complete
in the IIS server, during which time if any other user tries to hit this
server, with another "ligth transaction" for example, he has a very, very
bad response time, as the cpu is at its max, processing the other
transaction.

We don't developed the application, and have no idea of it's internal
workings. So, we can't really touch nothing of the code !

Everyone tell me that "Buffering enabled" for asp is good. But I'm begining
to belive that in this situation can be really bad, and hurting the overall
performance perceived by users.

Being "buffering" enabled means that the IIS server will complete the page
in a memory buffer, before sending it to the client, and during that time -
30 seconds -, the cpu will be at 100% level, disturbing all other users of
the IIS server.

As the client connects thru a slow phone line, and the returned data is so
big ( 1000Kb), then I think it has nosense to buffer the output of the asp
page in the first instance, as after that page is completed in memory, the
client will have to receive 1000Kb of html data over a phone line, which
will be very slow ... he well not perceive any improvement !

I think that if the asp bufferng is turned off, then IIS will be sending the
data to the client directly thru the TCP/IP channel, and as the client is
"slow" receiving the data, those working threads in the IIS server for that
client will suspend, until TCP/IP buffers clear ... during which time other
users could work normally with that server ... and in the end, the client
would receive the complete data in aprox. the same time.

Can someone of you comment on my judgement ? I'm rigth or completly mistaken
?

Thanks very much

If you disable buffering, then for every Response that is encountered
1) the execution of the page will stop while the response is sent to the
user
2) The ASP thread will block while the send is occurring
3) Once the send is completed, ASP will begin executing again.

You are probably right that CPU usage will decline, but this is only b/c the
threads will be blocked on the network. But, this also means that it will
take longer for a given ASP thread to finish and take another request, which
could mean that the number of requests that a given server could handle in
an hour/day would decline significantly. In other words, you might have a
better user experience, but it would be for fewer users.

One other thought is that disabling reponse buffering may have no effect.
For example:

For x = 1 to 1000000
strTemp = strTemp+ "<br>"
next

This would generate 100% CPU (50% on a dual proc) and would be completely
anaffected by any change to response buffering.


However this code:

for x = 1 to 1000000
response.write "<br>"
next

would be severely affected by changing the buffering.

Pat

"Lluis O" <llob.correobasurano.RemoveThis@menta.net> wrote in message
news:eCGRxA3OEHA.252@TK2MSFTNGP10.phx.gbl...
 > We've an asp application, which also uses some COM+ objects to access an
SQL
 > Server 2000 backend server.
 >
 > Our clients are all connecting thru phone dial-up lines, so they have
"slow"
 > lines. Some of the "transactions" could return something like 500Kb -
1000Kb
 > formated html data to the client. The asp buffering is enabled on the IIS
5
 > server.
 >
 > During those "heavy transactions", I observe that two DLLHOST processes
 > consume all available cpu in the IIS server, cpu which is split equally
50%
 > to each process. I've tracked that one of the process is serving the asp
 > pages, and the other is hosting the COM+ objects. The issolation level of
 > the IIS application is "medium".
 >
 > One of those "heavy transactions" can take as long as 30 seconds to
complete
 > in the IIS server, during which time if any other user tries to hit this
 > server, with another "ligth transaction" for example, he has a very, very
 > bad response time, as the cpu is at its max, processing the other
 > transaction.
 >
 > We don't developed the application, and have no idea of it's internal
 > workings. So, we can't really touch nothing of the code !
 >
 > Everyone tell me that "Buffering enabled" for asp is good. But I'm
begining
 > to belive that in this situation can be really bad, and hurting the
overall
 > performance perceived by users.
 >
 > Being "buffering" enabled means that the IIS server will complete the page
 > in a memory buffer, before sending it to the client, and during that
time -
 > 30 seconds -, the cpu will be at 100% level, disturbing all other users of
 > the IIS server.
 >
 > As the client connects thru a slow phone line, and the returned data is so
 > big ( 1000Kb), then I think it has nosense to buffer the output of the asp
 > page in the first instance, as after that page is completed in memory, the
 > client will have to receive 1000Kb of html data over a phone line, which
 > will be very slow ... he well not perceive any improvement !
 >
 > I think that if the asp bufferng is turned off, then IIS will be sending
the
 > data to the client directly thru the TCP/IP channel, and as the client is
 > "slow" receiving the data, those working threads in the IIS server for
that
 > client will suspend, until TCP/IP buffers clear ... during which time
other
 > users could work normally with that server ... and in the end, the client
 > would receive the complete data in aprox. the same time.
 >
 > Can someone of you comment on my judgement ? I'm rigth or completly
mistaken
 > ?
 >
 > Thanks very much
 >
 ><!-- ~MESSAGE_AFTER~ -->