How do Linux Threads compare with other OSs'?

Feature

Posix

Solaris

Win32

Linux

Kernel

BB

CL

DCE

FSU

JK

Lt

LWP

Nt

PCt

Pt

Qt

Rex

User-/Kernel-space

n/a

K&U

K

K

K

K

?

U

K

K

U

U

U

U

U

U

Cancellation

-

-

-

-

-

Priority Scheduling[1]

-

-

-

-

Priority InversionHandling [2]

?

-

-

-

-

-

-

Mutex Attributes

-

?

-

-

-

-

Shared and PrivateMutexes

-

?

-

-

-

-

-

-

Thread Attributes

-

-

-

-

Synchronization

-

-

Stack Size Control

-

-

Base Address Control[3]

-

n/a

-

-

-

-

-

Detached Threads

-

-

-

-

Joinable Threads

-

-

-

-

Per-ThreadData Handling Functions

-

-

-

Per-Thread SignalHandling

[4]

[8]

[4]

-

Condition Variables

?

?

-

-

-

Semaphores

-

-

-

-

Thread ID Comparison

-

-

-

[9]

-

Call-Once Functions

-

-

-

?

-

-

Thread Suspension[5]

-

-

-

-

-

Specifying Concurrency

-

[6]

-

-

-

-

-

[10]

-

Readers/WriterShare Locking [3]

-

-

-

-

-

-

-

-

-

Processor-specificThread Allocation

-

-

-

-

-

-

-

-

-

Fork All Threads[7]

-

-

-

-

-

-

-

Fork CallingThread Only [7]

-

?

-

-

-

-

NOTES:

1. Linux kernel-space threads areprocesses and are not handled differently from fork'ed tasks (unlike mostother multithreaded OS's). Therefore, process scheduling, cancelling, suspending,etc. is controlled via signals.
2. Posix and Solaris link threadpriorities with mutexes and use the priority of a blocked thread's mutexto alter the priority of the blocking thread. Win32 and Linux let the schedulerdetermine what thread to elevate in priority.
3. Solaris strangeness. Not applicable to mostother OS's.
4. Signals are received on a per-threadbasis, but threads share signal handlers for a given signal.
5. Posix specifies no functionalityfor suspending and resuming threads. Solaris implements it because theyneed it: the program can change certain thread's attributes unless it issuspended.
6. Multiprocessor systems only.
7. Win32 has no direct equivalent to unix'sfork() system call, but you can fake it with the CreateProcess() and CreateRemoteProcess()calls [and a little luck].
8. SIGIO and SIGALARM are multiplexed.
9. There is a function "nthread_self()"to get the ID of the calling thread.
10. You can specify how much user-levelthreads you will use at once. The number of kernel-level threads (i.e.concurrency level) is then determined as min([max number of threads touse],[number of available processors]).