Linked by Thom Holwerda on Wed 29th Aug 2007 00:28 UTC, submitted by diegocg
Windows Robert Love, a famous Linux kernel hacker, has written a blog entry with his thoughs on the recently posted Vista's network slowdown issue and the explanation given by Mark Russinovich: "Unlike DPCs, however, the Linux parallel does not consume nearly half of your CPU. There is no excusable reason why processing IP packets should so damagingly affect the system. Thus, this absolutely abysmal networking performance should be an issue in and of itself, but the Windows developers decided to focus on a secondary effect."
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RE: Awful situation
by Almafeta on Wed 29th Aug 2007 04:20 UTC in reply to "Awful situation"
Almafeta
Member since:
2007-02-22

Incidentally, is this MMCSS thing just MS speak for "When media is playing it lowers network speed," or is it some scheduler extension. If it is a scheduler extension, why can't these features be available to other non-media related realtime tasks, rather than being media centric; infact, why didn't they just make it part of the scheduler along with the other priority settings? (I'm curious - not just being rhetorical)


The Multimedia Class Scheudler Service is built into the scheduler. Any task in Vista can register itself with it to ensure that task is not interrupted.

I'd imagine that on a Vista-based server (if such an animal exists -- I'd imagine most servers are still on Windows 200X), the process that did the actual serving would be using this class to make sure that it never dropped, while non-critical and unimportant tasks (the GUI, background maintenance tests) were executed as secondary tasks.

Reply Parent Score: 1

RE[2]: Awful situation
by PlatformAgnostic on Wed 29th Aug 2007 04:50 in reply to "RE: Awful situation"
PlatformAgnostic Member since:
2006-01-02

MMCSS is not integrated with the scheduler. It's a usermode hack. It's a service that runs with high privilege that adjusts the priorities of other services. It is not useful for a server and likely won't exist on WS2008.

Reply Parent Score: 3

RE[3]: Awful situation
by segedunum on Wed 29th Aug 2007 08:24 in reply to "RE[2]: Awful situation"
segedunum Member since:
2005-07-06

MMCSS is not integrated with the scheduler. It's a usermode hack. It's a service that runs with high privilege that adjusts the priorities of other services. It is not useful for a server and likely won't exist on WS2008.

You miss the point. The problem here is with Vista's networking stack somewhere. The MMCSS hack was implemented as a response to it, but all processes can be affected, not just multimedia ones.

Reply Parent Score: 5