485 lines
10 KiB
C++
485 lines
10 KiB
C++
/* sched.cc: scheduler interface for Cygwin
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Copyright 2001, 2003, 2006, 2008, 2011 Red Hat, Inc.
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Written by Robert Collins <rbtcollins@hotmail.com>
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This file is part of Cygwin.
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This software is a copyrighted work licensed under the terms of the
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Cygwin license. Please consult the file "CYGWIN_LICENSE" for
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details. */
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#include "winsup.h"
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#include "miscfuncs.h"
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#include "cygerrno.h"
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#include "pinfo.h"
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/* for getpid */
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#include <unistd.h>
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#include "registry.h"
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/* Win32 priority to UNIX priority Mapping.
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For now, I'm just following the spec: any range of priorities is ok.
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There are probably many many issues with this...
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We don't want process's going realtime. Well, they probably could, but the issues
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with avoiding the priority values 17-22 and 27-30 (not supported before win2k)
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make that inefficient.
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However to complicate things most unixes use lower is better priorities.
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So we map -14 to 15, and 15 to 1 via (16- ((n+16) >> 1))
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we then map 1 to 15 to various process class and thread priority combinations
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Then we need to look at the threads vi process priority. As win95 98 and NT 4
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Don't support opening threads cross-process (unless a thread HANDLE is passed around)
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for now, we'll just use the priority class.
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The code and logic are present to calculate the priority for thread
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, if a thread handle can be obtained. Alternatively, if the symbols wouldn't be
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resolved until they are used
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we could support this on windows 2000 and ME now, and just fall back to the
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class only on pre win2000 machines.
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Lastly, because we can't assume that the pid we're given are Windows pids, we can't
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alter non-cygwin started programs.
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*/
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extern "C"
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{
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/* max priority for policy */
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int
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sched_get_priority_max (int policy)
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{
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if (policy < 1 || policy > 3)
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{
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set_errno (EINVAL);
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return -1;
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}
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return -14;
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}
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/* min priority for policy */
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int
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sched_get_priority_min (int policy)
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{
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if (policy < 1 || policy > 3)
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{
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set_errno (EINVAL);
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return -1;
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}
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return 15;
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}
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/* Check a scheduler parameter struct for valid settings */
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int
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valid_sched_parameters (const struct sched_param *param)
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{
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if (param->sched_priority < -14 || param->sched_priority > 15)
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{
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return 0;
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}
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return -1;
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}
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/* get sched params for process
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Note, I'm never returning EPERM,
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Always ESRCH. This is by design (If cygwin ever looks at paranoid security
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Walking the pid values is a known hole in some os's)
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*/
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int
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sched_getparam (pid_t pid, struct sched_param *param)
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{
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pid_t localpid;
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int winpri;
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if (!param || pid < 0)
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{
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set_errno (EINVAL);
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return -1;
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}
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localpid = pid ? pid : getpid ();
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DWORD Class;
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int ThreadPriority;
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HANDLE process;
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pinfo p (localpid);
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/* get the class */
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if (!p)
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{
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set_errno (ESRCH);
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return -1;
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}
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process = OpenProcess (PROCESS_QUERY_INFORMATION, FALSE, p->dwProcessId);
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if (!process)
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{
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set_errno (ESRCH);
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return -1;
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}
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Class = GetPriorityClass (process);
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CloseHandle (process);
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if (!Class)
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{
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set_errno (ESRCH);
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return -1;
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}
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ThreadPriority = THREAD_PRIORITY_NORMAL;
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/* calculate the unix priority.
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FIXME: windows 2000 supports ABOVE_NORMAL and BELOW_NORMAL class's
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So this logic just defaults those class factors to NORMAL in the calculations */
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switch (Class)
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{
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case IDLE_PRIORITY_CLASS:
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switch (ThreadPriority)
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{
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case THREAD_PRIORITY_IDLE:
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winpri = 1;
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break;
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case THREAD_PRIORITY_LOWEST:
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winpri = 2;
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break;
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case THREAD_PRIORITY_BELOW_NORMAL:
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winpri = 3;
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break;
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case THREAD_PRIORITY_NORMAL:
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winpri = 4;
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break;
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case THREAD_PRIORITY_ABOVE_NORMAL:
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winpri = 5;
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break;
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case THREAD_PRIORITY_HIGHEST:
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default:
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winpri = 6;
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break;
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}
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break;
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case HIGH_PRIORITY_CLASS:
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switch (ThreadPriority)
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{
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case THREAD_PRIORITY_IDLE:
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winpri = 1;
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break;
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case THREAD_PRIORITY_LOWEST:
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winpri = 11;
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break;
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case THREAD_PRIORITY_BELOW_NORMAL:
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winpri = 12;
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break;
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case THREAD_PRIORITY_NORMAL:
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winpri = 13;
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break;
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case THREAD_PRIORITY_ABOVE_NORMAL:
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winpri = 14;
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break;
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case THREAD_PRIORITY_HIGHEST:
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default:
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winpri = 15;
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break;
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}
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break;
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case NORMAL_PRIORITY_CLASS:
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default:
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switch (ThreadPriority)
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{
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case THREAD_PRIORITY_IDLE:
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winpri = 1;
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break;
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case THREAD_PRIORITY_LOWEST:
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winpri = 7;
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break;
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case THREAD_PRIORITY_BELOW_NORMAL:
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winpri = 8;
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break;
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case THREAD_PRIORITY_NORMAL:
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winpri = 9;
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break;
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case THREAD_PRIORITY_ABOVE_NORMAL:
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winpri = 10;
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break;
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case THREAD_PRIORITY_HIGHEST:
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default:
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winpri = 11;
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break;
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}
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break;
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}
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/* reverse out winpri = (16- ((unixpri+16) >> 1)) */
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/*
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winpri-16 = - (unixpri +16 ) >> 1
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-(winpri-16) = unixpri +16 >> 1
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(-(winpri-16)) << 1 = unixpri+16
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((-(winpri - 16)) << 1) - 16 = unixpri
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*/
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param->sched_priority = ((-(winpri - 16)) << 1) - 16;
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return 0;
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}
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/* get the scheduler for pid
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All process's on WIN32 run with SCHED_FIFO.
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So we just give an answer.
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(WIN32 uses a multi queue FIFO).
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*/
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int
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sched_getscheduler (pid_t pid)
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{
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if (pid < 0)
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return ESRCH;
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else
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return SCHED_FIFO;
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}
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/* get the time quantum for pid
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Implemented only for NT systems, it fails and sets errno to ESRCH
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for non-NT systems.
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*/
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int
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sched_rr_get_interval (pid_t pid, struct timespec *interval)
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{
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static const char quantable[2][2][3] =
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{{{12, 24, 36}, { 6, 12, 18}},
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{{36, 36, 36}, {18, 18, 18}}};
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/* FIXME: Clocktickinterval can be 15 ms for multi-processor system. */
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static const int clocktickinterval = 10;
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static const int quantapertick = 3;
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HWND forwin;
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DWORD forprocid;
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DWORD vfindex, slindex, qindex, prisep;
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long nsec;
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forwin = GetForegroundWindow ();
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if (!forwin)
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GetWindowThreadProcessId (forwin, &forprocid);
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else
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forprocid = 0;
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reg_key reg (HKEY_LOCAL_MACHINE, KEY_READ, L"SYSTEM", L"CurrentControlSet",
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L"Control", L"PriorityControl", NULL);
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if (reg.error ())
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{
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set_errno (ESRCH);
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return -1;
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}
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prisep = reg.get_dword (L"Win32PrioritySeparation", 2);
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pinfo pi (pid ? pid : myself->pid);
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if (!pi)
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{
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set_errno (ESRCH);
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return -1;
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}
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if (pi->dwProcessId == forprocid)
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{
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qindex = prisep & 3;
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qindex = qindex == 3 ? 2 : qindex;
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}
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else
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qindex = 0;
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vfindex = ((prisep >> 2) & 3) % 3;
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if (vfindex == 0)
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vfindex = wincap.is_server () || (prisep & 3) == 0 ? 1 : 0;
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else
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vfindex -= 1;
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slindex = ((prisep >> 4) & 3) % 3;
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if (slindex == 0)
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slindex = wincap.is_server () ? 1 : 0;
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else
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slindex -= 1;
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nsec = quantable[vfindex][slindex][qindex] / quantapertick
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* clocktickinterval * 1000000;
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interval->tv_sec = nsec / 1000000000;
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interval->tv_nsec = nsec % 1000000000;
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return 0;
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}
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/* set the scheduling parameters */
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int
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sched_setparam (pid_t pid, const struct sched_param *param)
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{
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pid_t localpid;
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int winpri;
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DWORD Class;
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int ThreadPriority;
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HANDLE process;
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if (!param || pid < 0)
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{
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set_errno (EINVAL);
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return -1;
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}
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if (!valid_sched_parameters (param))
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{
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set_errno (EINVAL);
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return -1;
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}
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/* winpri = (16- ((unixpri+16) >> 1)) */
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winpri = 16 - ((param->sched_priority + 16) >> 1);
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/* calculate our desired priority class and thread priority */
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if (winpri < 7)
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Class = IDLE_PRIORITY_CLASS;
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else if (winpri > 10)
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Class = HIGH_PRIORITY_CLASS;
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else
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Class = NORMAL_PRIORITY_CLASS;
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switch (Class)
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{
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case IDLE_PRIORITY_CLASS:
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switch (winpri)
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{
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case 1:
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ThreadPriority = THREAD_PRIORITY_IDLE;
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break;
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case 2:
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ThreadPriority = THREAD_PRIORITY_LOWEST;
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break;
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case 3:
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ThreadPriority = THREAD_PRIORITY_BELOW_NORMAL;
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break;
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case 4:
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ThreadPriority = THREAD_PRIORITY_NORMAL;
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break;
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case 5:
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ThreadPriority = THREAD_PRIORITY_ABOVE_NORMAL;
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break;
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case 6:
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ThreadPriority = THREAD_PRIORITY_HIGHEST;
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break;
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}
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break;
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case NORMAL_PRIORITY_CLASS:
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switch (winpri)
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{
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case 7:
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ThreadPriority = THREAD_PRIORITY_LOWEST;
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break;
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case 8:
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ThreadPriority = THREAD_PRIORITY_BELOW_NORMAL;
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break;
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case 9:
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ThreadPriority = THREAD_PRIORITY_NORMAL;
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break;
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case 10:
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ThreadPriority = THREAD_PRIORITY_ABOVE_NORMAL;
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break;
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case 11:
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ThreadPriority = THREAD_PRIORITY_HIGHEST;
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break;
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}
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break;
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case HIGH_PRIORITY_CLASS:
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switch (winpri)
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{
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case 12:
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ThreadPriority = THREAD_PRIORITY_BELOW_NORMAL;
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break;
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case 13:
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ThreadPriority = THREAD_PRIORITY_NORMAL;
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break;
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case 14:
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ThreadPriority = THREAD_PRIORITY_ABOVE_NORMAL;
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break;
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case 15:
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ThreadPriority = THREAD_PRIORITY_HIGHEST;
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break;
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}
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break;
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}
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localpid = pid ? pid : getpid ();
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pinfo p (localpid);
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/* set the class */
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if (!p)
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{
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set_errno (1); //ESRCH);
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return -1;
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}
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process =
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OpenProcess (PROCESS_SET_INFORMATION, FALSE, (DWORD) p->dwProcessId);
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if (!process)
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{
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set_errno (2); //ESRCH);
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return -1;
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}
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if (!SetPriorityClass (process, Class))
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{
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CloseHandle (process);
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set_errno (EPERM);
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return -1;
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}
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CloseHandle (process);
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return 0;
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}
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/* we map -14 to 15, and 15 to 1 via (16- ((n+16) >> 1)). This lines up with the allowed
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* valueswe return elsewhere in the sched* functions. We then map in groups of three to
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* allowed thread priority's. The reason for dropping accuracy while still returning
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* a wide range of values is to allow more flexible code in the future.
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*/
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int
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sched_set_thread_priority (HANDLE thread, int priority)
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{
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int real_pri;
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real_pri = 16 - ((priority + 16) >> 1);
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if (real_pri <1 || real_pri > 15)
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return EINVAL;
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if (real_pri < 4)
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real_pri = THREAD_PRIORITY_LOWEST;
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else if (real_pri < 7)
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real_pri = THREAD_PRIORITY_BELOW_NORMAL;
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else if (real_pri < 10)
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real_pri = THREAD_PRIORITY_NORMAL;
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else if (real_pri < 13)
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real_pri = THREAD_PRIORITY_ABOVE_NORMAL;
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else
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real_pri = THREAD_PRIORITY_HIGHEST;
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if (!SetThreadPriority (thread, real_pri))
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/* invalid handle, no access are the only expected errors. */
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return EPERM;
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return 0;
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}
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/* set the scheduler */
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int
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sched_setscheduler (pid_t pid, int policy,
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const struct sched_param *param)
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{
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/* on win32, you can't change the scheduler. Doh! */
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set_errno (ENOSYS);
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return -1;
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}
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/* yield the cpu */
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int
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sched_yield ()
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{
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SwitchToThread ();
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return 0;
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}
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}
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