Linked by Hadrien Grasland on Thu 19th May 2011 21:31 UTC
Hardware, Embedded Systems Having read the feedback resulting from my previous post on interrupts (itself resulting from an earlier OSnews Asks item on the subject), I've had a look at the way interrupts work on PowerPC v2.02, SPARC v9, Alpha and IA-64 (Itanium), and contribute this back to anyone who's interested (or willing to report any blatant flaw found in my posts). I've also tried to rework a bit my interrupt handling model to make it significantly clearer and have it look more like a design doc and less like a code draft.
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RE[4]: Locking benchmarks
by Neolander on Tue 24th May 2011 11:30 UTC in reply to "RE[3]: Locking benchmarks"
Neolander
Member since:
2010-03-08

Here's an interesting link describing an attack against apache caused by the fact that it uses a thread per connection. IIS is not subject to the same attack because it's asynchronous.

It may not be a completely fair comparison, but then it does suggest something about the scalability of each approach.

http://lwn.net/Articles/338407/

Actually, I still don't quite understand how this works, but it seems to me that the problem is that there a limitation to the number of connections which Apache can simultaneously keep open (or to the number of running threads, whichever is smaller). So for the comparison to be fair, IIS should have a similar limitation to the number of pending tasks.

And even then, the Apache guys have obviously not a good metric to detect if a connection is active or not here. If someone just keeps a connection open and does nothing with it, I'll simply ban that someone as soon as new incoming requests are coming. To follow the shop analogy : a cashier will be simply irritated by someone coming and paying with pennies if no one else is there, but if there are lots of people waiting in the queue, he'll use that excuse to either have the person pay in a faster way or kick it without its articles.

Edited 2011-05-24 11:31 UTC

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