ASP.NET
Performance
Host: Madhu Gopinathan, Architect Evangelist - Microsoft India
June
20, 2003
Deepak_MS: Hi friends
Deepak_MS: welcome to MSDN India chat...
Deepak_MS: today we have with us Madhu Gopinathan who works for Microsoft
who will discuss with you features of ASP.NET with special focus on
performance..
Deepak_MS: Madhu, lets start with some basics, what is in ASP.NET
that makes it better in terms of performance than classic ASP
madhug_ms: Good evening friends
madhug_ms: Welcome to ASP.NET performance chat
madhug_ms: We'll discuss about the following:
madhug_ms: Understand the cost of writing code, in the
managed code world, how to understand the cost and how to measure
it
madhug_ms: After all, the code that you write in ASP.NET
is managed code!!
madhug_ms: Second, we'll talk about performance considerations
while using various ASP.NET features
madhug_ms: Thirdly, how to monitor performance for ASP.NET
apps in production
Deepak_MS: (123456789): Hi can u tell me as performance wise what
is better ... I want to fill a dropdown list with data from a sql
table. 1) Dataadapter->dataset->fill it 2) sqlcommand->datareader->iterate
and add item in dropdown ... OR is there a better method
madhug_ms: Use data reader for fast, forward, read-only
access. If this data is used several times, then it makes sense to
cache it. Caching can be done at several levels: Cache the page itself,
or cache a fragment of the page.
madhug_ms: In IIS6, this cache sits at the kernel level
and this can give you excellent performance
madhug_ms: Or you can use the Cache class to store read-only
data in the middle tier
madhug_ms: I know this answer is long, but it depends
on whether the data you're populating is reference data, i.e. changes
infrequently or whether it changes every time the page is loaded
madhug_ms: Based on these considerations, you should use
one of the above mechanisms
Deepak_MS: (Neo-Reloaded): There is a famous question about inline
and code behind code...about performance...which one is better?
madhug_ms: w.r.t. performance, there is no difference.
Both are compiled.
madhug_ms: w.r.t. maintenance, there is big difference.
Code behind is a much better way to write real world applications
madhug_ms: Let me give you references to some excellent
articles on managed code performance
madhug_ms: I would recommend using CLRProfiler (see the
above articles) to understand characteristics of your code better
Deepak_MS: (venu): My Question: When I run an aspx page, the server
generates lots of scripts and HTML which increases the size of the
page and takes lots of time to download...is there a way to overcome
this?
madhug_ms: There are several things to consider here:
madhug_ms: Do you really need to use an ASP.NET control
or HTML control?
madhug_ms: Do you really need viewstate turned on for
all controls? Viewstate is enabled by default
madhug_ms: Instead of data grid, can you use repeater
control?
madhug_ms: These are some of the things to consider when
looking at the size of the page. Turn on tracing and look at the size
of each of the elements.
madhug_ms: See how these can be optimized.
madhug_ms: In special scenarios, you might want to look
at user controls to cut down on html generation
Deepak_MS: To add to that, here are times when you really don't need
view state..
Deepak_MS: classic example - a data grid being used to display 2000
records..
Deepak_MS: now if you are not going to be doing anything else other
than displaying the data, it makes sense to disable the viewstate
for the datagrid, because in effect, you are doubling the data that
is being transferred to the client - redundant data that is not being
used.
Deepak_MS: (Neo-Reloaded): Is there any security issues to be measured
in kernel caching? It is like isolated cache per app?
madhug_ms: NO. There is one cache in the kernel level
driver (HTTP.SYS). There is no code here, it is data being cached.
Deepak_MS: (Biswajit): In caching, there is no API support for caching
user controls, we have to use outputcache directive. Is that addressed
in 1.1?
madhug_ms: Use fragment caching to cache individual user
controls
Deepak_MS: (Neo-Reloaded): the scenario: if one application has more
500 aspx pages, and some 100 assemblies does this effect the performance
of the website? (if we bundle all in to a single assembly)?
madhug_ms: For a large web application, consider performing
pre-batch compilation
Deepak_MS: (YKK): What is the maximum number of simultaneous users
that can be allowed to be connected to an asp.net application. And
how to avoid crash of application errors like too many users connected.?
madhug_ms: There is no hard limit like that.
madhug_ms: For an application that needs to support a
very large number of users, use a web farm with network load balancing.
This will distribute the load to all members in the cluster.
madhug_ms: I mentioned an article previously which discusses
how to measure ASP.NET performance. This mentions performance counters
to measure various aspects of your application performance. Using
these, you should design your system appropriately (with adequate
hardware, resources etc)
madhug_ms: To scale out as the users increase, add more
members to your web farm.
madhug_ms: This way you can support a very large number
of users
Deepak_MS: (rajiv11882): OleDbAdapter.Update() takes hell lot of time.
With OleDbCommand object I can execute faster. But it is required
to be executed for each minor data change. How to speed up OleDbAdapter.Update()?
madhug_ms: Haven't heard this before.
madhug_ms: If this is a concern, you could use just commands
to update data and not use a dataset.
Deepak_MS: (YKK): Can I have reference of your article on ASP.NET
performance?
Deepak_MS: (Kiran): which is the best way to retrieve the data from
database, like in ADO recordset is used But in ADO.NET there are two
ways to retrieve the data that is oledbAdapter and oledbReader...(I
used these ways)..
madhug_ms: Ask yourself this question: Am I using this
data in a read-only fashion or one-time use?
madhug_ms: If so, use reader.
madhug_ms: If you want to keep the data around, do incremental
modifications etc. use adapter and a dataset.
madhug_ms: Dataset is similar to the disconnected recordset
of old ADO days.
madhug_ms: When monitoring ASP.NET application performance,
the following counters should be observed at a minimum
madhug_ms: Processor(_Total)\% Processor Time
madhug_ms: Process(aspnet_wp)\% Processor Time Process(aspnet_wp)\Private
Bytes Process(aspnet_wp)\Virtual Bytes Process(aspnet_wp)\Handle Count
.NET CLR Exceptions\# Exceps thrown / sec ASP.NET\Application Restarts
ASP.NET\Requests Rejected ASP.NET\Worker Process R
madhug_ms: ASP.NET\Application Restarts ASP.NET\Requests
Rejected ASP.NET\Worker Process Restarts Memory\Available Mbytes Web
Service\Current Connections Web Service\ISAPI Extension Requests/sec
madhug_ms: To debug performance and memory related issues,
please look at
Deepak_MS: (YKK): Can I have a reference article from where we can
get information to develop installer exe for a web application, that
can create virtual directory ,DSN connections etc. as we see in sample
application provided by ASP.net site?
madhug_ms: See installer walkthroughs in VS.NET documentation
Deepak_MS: With that we come to end of today's chat session...
Deepak_MS: Do join us next week for a session on developing and using
COM+ 1.5
