Ask Ingo Molnar About TUX

Ingo Molnar is the guy behind the TUX Web server, which produced those astounding SpecWeb results reported here last week. He's agreed to a Slashdot community interview. So ask away at the man who created what appears by some measures to be the world's most powerful Web server at present. Please make Ingo's job easier by first reading the LinuxToday articles (here's the first LW story, and here's the second LW story) commenting on the SpecWeb numbers and the background of how they were achieved, as well as Ingo's informative post in the initial Slashdot story, and the SpecWeb results themselves. The moderators may have no mercy otherwise.

Comments

Version 1

[Anonymous Coward]

This is a version 1 of the web server, and it has proven itself to be pretty nifty when it comes to serving both static webpages (through a kernel level httpd) and dynamic webpages. Do you see TuX getting more lean and faster as time wears on, past versions 2, 3, ... or do you see it getting bogged down in mostly unnecessary cruft and bloat?

Will there be a way to port an existing Apache configuration across to the TuX configuration? How about IIS, Netscape, Zeus, etc? Will TuX have the option of a GUI setup screen for those who don't like the command line? Will TuX have a simple installer?

What is TUX's goal?

[nd]

What is the target purpose of TUX? From the benchmarks, it appears to be for very high traffic sites. I ask because I'm curious if that is its specific purpose, or does it serve well in other areas as well (i.e, Apache flexibility)?

This is important because it will also help indicate what Red Hat's stance will likely be in either replacing Apache with TUX or just including it in their Professional distributions.

It works with Apache...

[Ex Machina]

It works with Apache but is TUX generic enough to be interfaced with another server?

Load balancing

[Ex Machina]

Does/Will TUX provide any sort of load balancing for a cluster of heterogenous TUX servers?

Kernel modules decrease portability?

[11223]

You mentioned in the second Linux Today article that you intend to integrate TUX with Apache. However, Apache has always been a cross-platform server and is heavily used on *BSD and Solaris. Do you feel that this integration will undermine the portability work of the Apache team, or will it simply provide an incentive for web servers to be running Linux? If you intend to encourage people to move to Linux, can a similar idea as TUX be applied to an SQL server to make up for the speed deficit between Linux SQL servers and Microsoft SQL?

Threading and Linux

[Chainsaw]

Unix programmers seems to dislike using threads in their applications. After all, they can just fork(); and run along instead of using the thread functions. But, that's not important right now.

What is your opinion on the current thread implementation in the Linux kernel compared to systems designed from the ground up to support threads (like BeOS, OS/2 and Windows NT)? In which way could the kernel developers make the threads work better?

Performance using dynamic content.

[Paladin128]

How would TUX perform using CGI/Servlets/PHP/etc. compared to Apache or IIS? The ability to serve static pages fast is not that useful in the real world, as all the sites that get really big hits-per-second are those with dynamic content (Yahoo, Slashdot, Amazon.com, etc.)


"Evil beware: I'm armed to the teeth and packing a hampster!"

Integration into RedHat?

[ErMaC]

How will the TUX Webserver integrate with RedHat's Linux distributions? Will RedHat create a special distribution with an identical setup to yours? Will RedHat start releasing more specialized distributions, preferably ones more suited to a secure server environment but focused on performance like your setup was?

As it is RedHat seems too insecure and bloated for a streamlined server environment. Ideal would be installation options where I can say "This server will do these 3 things (i.e. DNS, Mail, HTTP) so make it suited for that and nothing else." This kind of flexibility would be a HUGE boon to the server market, giving customers a high performance machine running TUX + Apache that was secure and did the functions they needed it to.


Yea that was a long question, you can chop off last paragraph if you like. Hehe, insecure and bloated, can we say WinNT/2K?

"I want to get more into theory, because everything works in theory." -John Cash

Caching

[JohnZed]

I have a few questions about TUX's caching system. Before I go any further, I want to say that I'm incredibly impressed by the results. I've been following specWeb99 for a while and have been wondering when someone would manage to build a great dynamic cache like this one. I hope it'll get the wide acceptance it seems to deserve.
First, it seems that basically the entire test file set was loaded into memory ahead of time for use by TUX. How adaptable is TUX to more dynamic, limited-memory environments in terms of setting cache size limitations, selectivity (e.g. "cache all .GIFs, but not .html files"), and expiration/reloading algorithms?
Second, can a tux module programmer modify the basic tux commands, or do they always do the same thing? For instance, if I were adapting TUX to work with a web proxy cache, I'd want TUX_ACTION_GET_OBJECT to actually go out over the network and do a GET request if it couldn't find a requested object in the cache. You can imagine lots of other circumstances where this would come up as well.
Third, is it possible to execute more than one user-space TUX module at one time?
Fourth, when can we play with the code?
Thanks a lot!
--JRZ

Relative Impact

[Caballero]

TUX includes a variety of kernel and apache changes. Can you give a rough measure of how each of the changes improved the http performance? I'm interested in the amount of improvement as well as why it improved performance. Do those particular changes have negative impact on the performance of other applications?

TUX Architecture

[dweezil]

You appear to have take an "architectural" approach to designing TUX, so I have some architectural questions.

1. The choice of a kernel space implementation is probably going to be a controversial one. You suggest that HTTP is commonly used enough to go in the kernel just as TCP/IP did years ago. What performance or architectural advantages do you see to moving application protocols into the kernel that cannot be achieved in user space?
2. What is your approach to concurence? In particular, you refer to "event driven". What do you mean by that and what did you choose as the core to your event engine? Also, how do you handle threading to scale on SMP machines?
3. Are there any plans to generalize the infrastructure elements of TUX so that other protocol servers can take advantage of the TUX architecture and also go fast as hell?

Re:Versions for other OSs?

[Jason Earl]

Actually there is a specific feature that would probably make TUX incompatible with the BSDs. TUX is licensed under the GPL and the BSD maintainers would probably be very reluctant to port it to their OSes. Especially since it is possible that this would require them to release the derivative work under the GPL.

Which leads to the obvious question for Ingo. You mention a specific disclaimer that would allow the Apache to be linked with TUX, do the BSDs get the same privilege?

Not that I particularly care, as I am not a BSD user, but the putting such a nifty program as TUX under the GPL is bound to cause weeping and gnashing of teeth in the BSD camp. Which brings up another question. How much pressure do you get from your BSD compatriots to release software like this under a more liberal BSD-friendly license?

How are benchmarks used?

[ChrisDolan]

Have you tuned TUX for any particular benchmarks, or do you just write it as best you can and throw it in the ring? If it's tuned to some benchmarks, does that hurt its performance on other benchmarks?

Have any benchmark tests ever been particularly useful for revealing bugs/inefficiencies in your code? That is, are the benchmarks tools to you, or are they just the end product?