Parallel Computing Platform: An Integrated Approach to Tooling
- Posted: Oct 10, 2008 at 10:05 AM
- 56,296 Views
- 2 Comments
Loading User Information from Channel 9
Something went wrong getting user information from Channel 9
Loading User Information from MSDN
Something went wrong getting user information from MSDN
Loading Visual Studio Achievements
Something went wrong getting the Visual Studio Achievements
Right click “Save as…”
Comments have been closed since this content was published more than 30 days ago, but if you'd like to continue the conversation,
please create a new thread in our Forums,
or
Contact Us and let us know.
Follow the Discussion
Oops, something didn't work.
What does this mean?
Following an item on Channel 9 allows you to watch for new content and comments that you are interested in. You need to be signed in to Channel 9 to use this feature.What does this mean?
Following an item on Channel 9 allows you to watch for new content and comments that you are interested in and view them all on your notifications page.sign up for email notifications?
You have to be careful with parallel execution when it comes to disk I/O.
If each thread is accessing a file, the whole thing slows down to a crawl as the hard disc read head has to jump to each file every 20ms. It would be MUCH better if the operating system could allocate more time to read a file before it allowed a context switch. say 500ms. that would allow more data to be retrieved from the hard disc, less head thrash, less time waiting for the head to move, and performance would go up greatly.
Just try creating 2 or more zip archives at the same time, then time it again but only doing 1 at a time. Winrar has a feature where it will wait (probably using a global mutex) for other winrar windows to finish before the next one starts.
You can context switch CPU threads till the cows come home, but a phsical device needs more time to read/write when the head arrives.
Remove this comment
Remove this thread
close