2 This file is a part of libcds - Concurrent Data Structures library
4 (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017
6 Source code repo: http://github.com/khizmax/libcds/
7 Download: http://sourceforge.net/projects/libcds/files/
9 Redistribution and use in source and binary forms, with or without
10 modification, are permitted provided that the following conditions are met:
12 * Redistributions of source code must retain the above copyright notice, this
13 list of conditions and the following disclaimer.
15 * Redistributions in binary form must reproduce the above copyright notice,
16 this list of conditions and the following disclaimer in the documentation
17 and/or other materials provided with the distribution.
19 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
20 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
22 DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
23 FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
25 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
26 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
27 OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 #ifndef CDSLIB_OS_LINUX_TOPOLOGY_H
32 #define CDSLIB_OS_LINUX_TOPOLOGY_H
34 #ifndef CDSLIB_OS_TOPOLOGY_H
35 # error "<cds/os/topology.h> must be included instead"
38 #include <cds/details/defs.h>
39 #include <cds/threading/model.h>
41 #include <sys/syscall.h>
44 namespace cds { namespace OS {
45 /// Linux-specific wrappers
46 CDS_CXX11_INLINE_NAMESPACE namespace Linux {
50 The implementation assumes that processor IDs are in numerical order
51 from 0 to N - 1, where N - count of processor in the system
56 static unsigned int s_nProcessorCount;
60 /// Logical processor count for the system
61 static unsigned int processor_count()
63 return s_nProcessorCount;
66 /// Get current processor number
68 Caveat: \p current_processor calls system \p sched_getcpu function
69 that may not be defined for target system (\p sched_getcpu is available since glibc 2.6).
70 If \p sched_getcpu is not defined the function emulates "current processor number" using
71 thread-specific data. You may manually disable the \p sched_getcpu usage compiling with
72 <tt>-DCDS_LINUX_NO_sched_getcpu</tt>.
74 static unsigned int current_processor()
76 // Compile libcds with -DCDS_LINUX_NO_sched_getcpu if your linux does not have sched_getcpu (glibc version less than 2.6)
77 # if !defined(CDS_LINUX_NO_sched_getcpu) && defined(SYS_getcpu)
78 int nProcessor = ::sched_getcpu();
79 return nProcessor == -1 ? 0 : (unsigned int) nProcessor;
81 // Use fake "current processor number" assigned for current thread
82 return (unsigned int) threading::Manager::fake_current_processor();
85 Another way (for x86/amd64 only)
87 Using cpuid and APIC ID (http://www.scss.tcd.ie/Jeremy.Jones/GetCurrentProcessorNumberXP.htm)
96 - cpuid is full sync barrier
97 - it is only for x86/amd64 architecture
102 /// Synonym for \ref current_processor
103 static unsigned int native_current_processor()
105 return current_processor();
115 #ifndef CDS_CXX11_INLINE_NAMESPACE_SUPPORT
116 using Linux::topology;
118 }} // namespace cds::OS
120 #endif // #ifndef CDSLIB_OS_LINUX_TOPOLOGY_H