source: rtems/cpukit/score/src/schedulersetaffinity.c @ c5831a3f

4.115
Last change on this file since c5831a3f was c5831a3f, checked in by Sebastian Huber <sebastian.huber@…>, on 04/09/14 at 13:07:54

score: Add clustered/partitioned scheduling

Clustered/partitioned scheduling helps to control the worst-case
latencies in the system. The goal is to reduce the amount of shared
state in the system and thus prevention of lock contention. Modern
multi-processor systems tend to have several layers of data and
instruction caches. With clustered/partitioned scheduling it is
possible to honour the cache topology of a system and thus avoid
expensive cache synchronization traffic.

We have clustered scheduling in case the set of processors of a system
is partitioned into non-empty pairwise-disjoint subsets. These subsets
are called clusters. Clusters with a cardinality of one are partitions.
Each cluster is owned by exactly one scheduler instance.
  • Property mode set to 100644
File size: 1.5 KB
Line 
1/*
2 * Copyright (c) 2014 embedded brains GmbH.  All rights reserved.
3 *
4 *  embedded brains GmbH
5 *  Dornierstr. 4
6 *  82178 Puchheim
7 *  Germany
8 *  <rtems@embedded-brains.de>
9 *
10 * The license and distribution terms for this file may be
11 * found in the file LICENSE in this distribution or at
12 * http://www.rtems.org/license/LICENSE.
13 */
14
15#if HAVE_CONFIG_H
16  #include "config.h"
17#endif
18
19#include <rtems/score/schedulerimpl.h>
20
21#if defined(__RTEMS_HAVE_SYS_CPUSET_H__)
22
23bool _Scheduler_Set_affinity(
24  Thread_Control          *the_thread,
25  size_t                   cpusetsize,
26  const cpu_set_t         *cpuset
27)
28{
29  bool ok;
30
31  if ( _CPU_set_Is_large_enough( cpusetsize ) ) {
32#if defined(RTEMS_SMP)
33    uint32_t cpu_count = _SMP_Get_processor_count();
34    uint32_t cpu_index;
35
36    ok = false;
37
38    for ( cpu_index = 0 ; cpu_index < cpu_count ; ++cpu_index ) {
39      if ( CPU_ISSET_S( (int) cpu_index, cpusetsize, cpuset ) ) {
40        const Scheduler_Control *scheduler_of_cpu =
41          _Scheduler_Get_by_CPU_index( cpu_index );
42
43        if ( scheduler_of_cpu != NULL ) {
44          ok = ( *scheduler_of_cpu->Operations.set_affinity )(
45            scheduler_of_cpu,
46            the_thread,
47            cpusetsize,
48            cpuset
49          );
50        }
51
52        break;
53      }
54    }
55#else
56    ok = _Scheduler_default_Set_affinity_body(
57      _Scheduler_Get( the_thread ),
58      the_thread,
59      cpusetsize,
60      cpuset
61    );
62#endif
63  } else {
64    ok = false;
65  }
66
67  return ok;
68}
69
70#endif /* defined(__RTEMS_HAVE_SYS_CPUSET_H__) */
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