PORTABILITYISSUES manual page

From a2bafc3ea86514e5b1fd67d4ae2b427b18ccbf33 Mon Sep 17 00:00:00 2001 From: rpj Date: Fri, 6 May 2005 01:36:35 +0000 Subject: '' --- manual/PortabilityIssues.html | 718 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 718 insertions(+) create mode 100644 manual/PortabilityIssues.html (limited to 'manual/PortabilityIssues.html') diff --git a/manual/PortabilityIssues.html b/manual/PortabilityIssues.html new file mode 100644 index 0000000..e828ae3 --- /dev/null +++ b/manual/PortabilityIssues.html @@ -0,0 +1,718 @@ + + + + + PORTABILITYISSUES manual page + + + + + + + +

Table of Contents

Name

Portability issues

Synopsis

Thread priority

Description

Thread priority

POSIX defines a single contiguous range +of numbers that determine a thread's priority. Win32 defines priority +classes - and priority levels relative to these classes. Classes are +simply priority base levels that the defined priority levels are +relative to such that, changing a process's priority class will +change the priority of all of it's threads, while the threads retain +the same relativity to each other.

A Win32 system defines a single +contiguous monotonic range of values that define system priority +levels, just like POSIX. However, Win32 restricts individual threads +to a subset of this range on a per-process basis.

The following table shows the base +priority levels for combinations of priority class and priority value +in Win32.

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

+ + +	+ Process Priority Class +	+ Thread Priority Level +
+ 1 +	+ IDLE_PRIORITY_CLASS +	+ THREAD_PRIORITY_IDLE +
+ 1 +	+ BELOW_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_IDLE +
+ 1 +	+ NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_IDLE +
+ 1 +	+ ABOVE_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_IDLE +
+ 1 +	+ HIGH_PRIORITY_CLASS +	+ THREAD_PRIORITY_IDLE +
+ 2 +	+ IDLE_PRIORITY_CLASS +	+ THREAD_PRIORITY_LOWEST +
+ 3 +	+ IDLE_PRIORITY_CLASS +	+ THREAD_PRIORITY_BELOW_NORMAL +
+ 4 +	+ IDLE_PRIORITY_CLASS +	+ THREAD_PRIORITY_NORMAL +
+ 4 +	+ BELOW_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_LOWEST +
+ 5 +	+ IDLE_PRIORITY_CLASS +	+ THREAD_PRIORITY_ABOVE_NORMAL +
+ 5 +	+ BELOW_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_BELOW_NORMAL +
+ 5 +	+ Background NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_LOWEST +
+ 6 +	+ IDLE_PRIORITY_CLASS +	+ THREAD_PRIORITY_HIGHEST +
+ 6 +	+ BELOW_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_NORMAL +
+ 6 +	+ Background NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_BELOW_NORMAL +
+ 7 +	+ BELOW_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_ABOVE_NORMAL +
+ 7 +	+ Background NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_NORMAL +
+ 7 +	+ Foreground NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_LOWEST +
+ 8 +	+ BELOW_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_HIGHEST +
+ 8 +	+ NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_ABOVE_NORMAL +
+ 8 +	+ Foreground NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_BELOW_NORMAL +
+ 8 +	+ ABOVE_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_LOWEST +
+ 9 +	+ NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_HIGHEST +
+ 9 +	+ Foreground NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_NORMAL +
+ 9 +	+ ABOVE_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_BELOW_NORMAL +
+ 10 +	+ Foreground NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_ABOVE_NORMAL +
+ 10 +	+ ABOVE_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_NORMAL +
+ 11 +	+ Foreground NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_HIGHEST +
+ 11 +	+ ABOVE_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_ABOVE_NORMAL +
+ 11 +	+ HIGH_PRIORITY_CLASS +	+ THREAD_PRIORITY_LOWEST +
+ 12 +	+ ABOVE_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_HIGHEST +
+ 12 +	+ HIGH_PRIORITY_CLASS +	+ THREAD_PRIORITY_BELOW_NORMAL +
+ 13 +	+ HIGH_PRIORITY_CLASS +	+ THREAD_PRIORITY_NORMAL +
+ 14 +	+ HIGH_PRIORITY_CLASS +	+ THREAD_PRIORITY_ABOVE_NORMAL +
+ 15 +	+ HIGH_PRIORITY_CLASS +	+ THREAD_PRIORITY_HIGHEST +
+ 15 +	+ HIGH_PRIORITY_CLASS +	+ THREAD_PRIORITY_TIME_CRITICAL +
+ 15 +	+ IDLE_PRIORITY_CLASS +	+ THREAD_PRIORITY_TIME_CRITICAL +
+ 15 +	+ BELOW_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_TIME_CRITICAL +
+ 15 +	+ NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_TIME_CRITICAL +
+ 15 +	+ ABOVE_NORMAL_PRIORITY_CLASS +	+ THREAD_PRIORITY_TIME_CRITICAL +
+ 16 +	+ REALTIME_PRIORITY_CLASS +	+ THREAD_PRIORITY_IDLE +
+ 17 +	+ REALTIME_PRIORITY_CLASS +	+ -7 +
+ 18 +	+ REALTIME_PRIORITY_CLASS +	+ -6 +
+ 19 +	+ REALTIME_PRIORITY_CLASS +	+ -5 +
+ 20 +	+ REALTIME_PRIORITY_CLASS +	+ -4 +
+ 21 +	+ REALTIME_PRIORITY_CLASS +	+ -3 +
+ 22 +	+ REALTIME_PRIORITY_CLASS +	+ THREAD_PRIORITY_LOWEST +
+ 23 +	+ REALTIME_PRIORITY_CLASS +	+ THREAD_PRIORITY_BELOW_NORMAL +
+ 24 +	+ REALTIME_PRIORITY_CLASS +	+ THREAD_PRIORITY_NORMAL +
+ 25 +	+ REALTIME_PRIORITY_CLASS +	+ THREAD_PRIORITY_ABOVE_NORMAL +
+ 26 +	+ REALTIME_PRIORITY_CLASS +	+ THREAD_PRIORITY_HIGHEST +
+ 27 +	+ REALTIME_PRIORITY_CLASS +	+ 3 +
+ 28 +	+ REALTIME_PRIORITY_CLASS +	+ 4 +
+ 29 +	+ REALTIME_PRIORITY_CLASS +	+ 5 +
+ 30 +	+ REALTIME_PRIORITY_CLASS +	+ 6 +
+ 31 +	+ REALTIME_PRIORITY_CLASS +	+ THREAD_PRIORITY_TIME_CRITICAL +

+ +

Windows NT: Values -7, -6, -5, -4, -3, 3, +4, 5, and 6 are not supported.

As you can see, the real priority levels +available to any individual Win32 thread are non-contiguous.

An application using Pthreads-w32 should +not make assumptions about the numbers used to represent thread +priority levels, except that they are monotonic between the values +returned by sched_get_priority_min() and sched_get_priority_max(). +E.g. Windows 95, 98, NT, 2000, XP make available a non-contiguous +range of numbers between -15 and 15, while at least one version of +WinCE (3.0) defines the minimum priority (THREAD_PRIORITY_LOWEST) as +5, and the maximum priority (THREAD_PRIORITY_HIGHEST) as 1.

Internally, pthreads-win32 maps any +priority levels between THREAD_PRIORITY_IDLE and +THREAD_PRIORITY_LOWEST to THREAD_PRIORITY_LOWEST, or between +THREAD_PRIORITY_TIME_CRITICAL and THREAD_PRIORITY_HIGHEST to +THREAD_PRIORITY_HIGHEST. Currently, this also applies to +REALTIME_PRIORITY_CLASS even if levels -7, -6, -5, -4, -3, 3, 4, 5, +and 6 are supported.

If it wishes, a Win32 application using +pthreads-w32 can use the Win32 defined priority macros +THREAD_PRIORITY_IDLE through THREAD_PRIORITY_TIME_CRITICAL.

Author

Ross Johnson for use with Pthreads-w32.

Name

Synopsis

Description

Author

See also