Mark Russinovich On Vista Network Slowdown

koro666 writes "In his latest blog post, Mark Russinovich analyzes the network slowdown experienced by some users when playing multimedia content. 'Tests of MMCSS during Vista development showed that... heavy network traffic can cause enough long-running DPCs to prevent playback threads from keeping up with their media streaming requirements, resulting in glitching. MMCSS' glitch-resistant mechanisms were therefore extended to include throttling of network activity. It does so by issuing a command to the NDIS device driver... [to] pass along, at most 10 packets per millisecond (10,000 packets per second)... [T]he networking team is actively working with the MMCSS team on a fix that allows for not so dramatically penalizing network traffic, while still delivering a glitch-resistant experience.'"

Comments

Re:Failed engineering

[CastrTroy]

Or to put it a little simpler, people who need more than 10,000 packets per second, probably shouldn't be using their machine to listen to music. or if they do, they shouldn't worry about the speed too much. Let's do some math, 10,000 packets, at a standard ethernet packet size of 1.5 K, you would get a transfer rate of 1.5 MB/s, or in more appropriate data transfer units, about 12 Mb/s. That's way faster than most internet connections available on cosumer PCs. I also know quite a few people with 10 Mb hubs still operating on their network. It seems odd that they would have chosen some arbitrary number of packets, rather than have the computer try to analyze what's going on, and try to limit the number of packets only enough so that it doesn't make the audio skip. Possibly even by dropping packets, instead of skipping the audio, the problem would completely solve itself by having the connection slow itself down due to the dropped packets. However, I find this to be a little unnecessary. No other OS on the planet has to throttle the network speed to play MP3s without skipping. Why does Vista?

Re:Hang on a minute...

[night_flyer]

640K of memory should be enough for anybody.