Priority class

NTDEV
1

Hi,
This is mostly general question. I was curious as to when is it Ok to run
thread with the
high priority class ?.

Shailesh Jain

2

> when is it Ok to run thread with the high priority class

…when you know what you are doing , are willing to yield the CPU, and do it pretty quickly.

Normally such thread would spend most of its lifetime in a blocked state, waking up when some certain even occurs, doing its job, and blocking again. Otherwise you may get a serious performance degradation at the system level on MP system and make UP one just unusable…

Anton Bassov

3

>high priority class ?.

IO-bound thread which spends most of it life waiting. For instance, if it does nothing then IRP submission and waiting for its completion.

–
Maxim S. Shatskih
Windows DDK MVP
xxxxx@storagecraft.com
http://www.storagecraft.com

4

The simplistic answer: "When you are willing to accept the consequences of
doing so". Unfortunately, that's usually the best answer. Sometimes, the
consequences are so minor that it doesn't matter in terms of the impact on
the system, but the high priority is critical to the behavior of the driver
or the application. But when the impact becomes annoying, that is, it
detectably interferes with the overall system behavior in ways that affect
applications, other driver threads, or (for application threads) other
applications, then you have to reconsider what is happening, and perhaps
redesign the code to not require a high-priority thread.

There is no one simple answer. This is a classic "it depends." style
question.
joe

From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of shailesh jain
Sent: Friday, July 31, 2009 7:14 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] Priority class

Hi,
This is mostly general question. I was curious as to when is it Ok to run
thread with the
high priority class ?.

Shailesh Jain
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