我们从Python开源项目中，提取了以下50个代码示例，用于说明如何使用os.sysconf()。
def _close_fds(): try: max_fd = os.sysconf("SC_OPEN_MAX") except ValueError as e: logger.warn(repr(e) + ' while get max fds of a process') max_fd = 65536 for i in xrange(3, max_fd): try: os.close(i) except OSError: pass
def _check_system_limits(): global _system_limits_checked, _system_limited if _system_limits_checked: if _system_limited: raise NotImplementedError(_system_limited) _system_limits_checked = True try: import os nsems_max = os.sysconf("SC_SEM_NSEMS_MAX") except (AttributeError, ValueError): # sysconf not available or setting not available return if nsems_max == -1: # indetermine limit, assume that limit is determined # by available memory only return if nsems_max >= 256: # minimum number of semaphores available # according to POSIX return _system_limited = "system provides too few semaphores (%d available, 256 necessary)" % nsems_max raise NotImplementedError(_system_limited)
def _detect_ncpus(): """Detect the number of effective CPUs in the system""" # Snippet taken from ParallelPython # For Linux, Unix and MacOS if hasattr(os, "sysconf"): if "SC_NPROCESSORS_ONLN" in os.sysconf_names: #Linux and Unix ncpus = os.sysconf("SC_NPROCESSORS_ONLN") if isinstance(ncpus, int) and ncpus > 0: return ncpus else: #MacOS X return int(os.popen2("sysctl -n hw.ncpu")[1].read()) #for Windows if "NUMBER_OF_PROCESSORS" in os.environ: ncpus = int(os.environ["NUMBER_OF_PROCESSORS"]) if ncpus > 0: return ncpus #return the default value return 1
def check_enough_semaphores(): """Check that the system supports enough semaphores to run the test.""" # minimum number of semaphores available according to POSIX nsems_min = 256 try: nsems = os.sysconf("SC_SEM_NSEMS_MAX") except (AttributeError, ValueError): # sysconf not available or setting not available return if nsems == -1 or nsems >= nsems_min: return raise unittest.SkipTest("The OS doesn't support enough semaphores " "to run the test (required: %d)." % nsems_min) # # Creates a wrapper for a function which records the time it takes to finish #
def detect_number_of_cores(): """ Detects the number of cores on a system. Cribbed from pp. """ # Linux, Unix and MacOS: if hasattr(os, "sysconf"): if "SC_NPROCESSORS_ONLN" in os.sysconf_names: # Linux & Unix: ncpus = os.sysconf("SC_NPROCESSORS_ONLN") if isinstance(ncpus, int) and ncpus > 0: return ncpus else: # OSX: return int(subprocess.check_output(["sysctl", "-n", "hw.ncpu"])) # Windows: if "NUMBER_OF_PROCESSORS" in os.environ: ncpus = int(os.environ["NUMBER_OF_PROCESSORS"]); if ncpus > 0: return ncpus return 1 # Default
def _check_system_limits(): global _system_limits_checked, _system_limited if _system_limits_checked: if _system_limited: raise NotImplementedError(_system_limited) _system_limits_checked = True try: nsems_max = os.sysconf("SC_SEM_NSEMS_MAX") except (AttributeError, ValueError): # sysconf not available or setting not available return if nsems_max == -1: # indetermined limit, assume that limit is determined # by available memory only return if nsems_max >= 256: # minimum number of semaphores available # according to POSIX return _system_limited = "system provides too few semaphores (%d available, 256 necessary)" % nsems_max raise NotImplementedError(_system_limited)
def cpuCount(): ''' Returns the number of CPUs in the system ''' if sys.platform == 'win32': try: num = int(os.environ['NUMBER_OF_PROCESSORS']) except (ValueError, KeyError): num = -1 elif sys.platform == 'darwin': try: num = int(os.popen('sysctl -n hw.ncpu').read()) except ValueError: num = -1 else: try: num = os.sysconf('SC_NPROCESSORS_ONLN') except (ValueError, OSError, AttributeError): num = -1 return num
def detectCPUs(): """ Detects the number of CPUs on a system. Cribbed from pp. """ # Linux, Unix and MacOS: if hasattr(os, "sysconf"): if "SC_NPROCESSORS_ONLN" in os.sysconf_names: # Linux & Unix: ncpus = os.sysconf("SC_NPROCESSORS_ONLN") if isinstance(ncpus, int) and ncpus > 0: return ncpus else: # OSX: return int(capture(['sysctl', '-n', 'hw.ncpu'])) # Windows: if "NUMBER_OF_PROCESSORS" in os.environ: ncpus = int(os.environ["NUMBER_OF_PROCESSORS"]) if ncpus > 0: return ncpus return 1 # Default
def make_post_exec_msg(start_time: datetime=None, comment: str=None) -> str: """Build Post-Execution Message with information about RAM and Time.""" use, al, msg = 0, 0, "" if sys.platform.startswith(("win", "darwin")): msg = "No information about RAM usage available on non-Linux systems." elif sys.platform.startswith("linux"): use = int(resource.getrusage(resource.RUSAGE_SELF).ru_maxrss * resource.getpagesize() if resource else 0) al = int(os.sysconf('SC_PAGE_SIZE') * os.sysconf('SC_PHYS_PAGES') if hasattr(os, "sysconf") else 0) msg += f"""Total Max Memory Used: ~{use / al:.2%} Percent. { bytes2human(use) } ({ use } bytes) of { bytes2human(al) } ({ al } bytes) of total RAM Memory.\n""" if start_time: _t = datetime.now() - start_time msg += f"Total Working Time: ~{ timedelta2human(_t) } ({ _t }).\n" if comment: msg += str(comment).strip() log.debug("Preparing Simple Post-Execution Messages.") atexit.register(log.info, msg) return msg
def cpu_count(): ''' Returns the number of CPUs in the system ''' if sys.platform == 'win32': try: num = int(os.environ['NUMBER_OF_PROCESSORS']) except (ValueError, KeyError): num = 0 elif 'bsd' in sys.platform or sys.platform == 'darwin': comm = '/sbin/sysctl -n hw.ncpu' if sys.platform == 'darwin': comm = '/usr' + comm try: with os.popen(comm) as p: num = int(p.read()) except ValueError: num = 0 else: try: num = os.sysconf('SC_NPROCESSORS_ONLN') except (ValueError, OSError, AttributeError): num = 0 if num >= 1: return num else: raise NotImplementedError('cannot determine number of cpus')
def jobs(self): """ Find the amount of cpu cores to set the default amount of tasks executed in parallel. At runtime the options can be obtained from :py:const:`waflib.Options.options` :: from waflib.Options import options njobs = options.jobs :return: the amount of cpu cores :rtype: int """ count = int(os.environ.get('JOBS', 0)) if count < 1: if 'NUMBER_OF_PROCESSORS' in os.environ: # on Windows, use the NUMBER_OF_PROCESSORS environment variable count = int(os.environ.get('NUMBER_OF_PROCESSORS', 1)) else: # on everything else, first try the POSIX sysconf values if hasattr(os, 'sysconf_names'): if 'SC_NPROCESSORS_ONLN' in os.sysconf_names: count = int(os.sysconf('SC_NPROCESSORS_ONLN')) elif 'SC_NPROCESSORS_CONF' in os.sysconf_names: count = int(os.sysconf('SC_NPROCESSORS_CONF')) if not count and os.name not in ('nt', 'java'): try: tmp = self.cmd_and_log(['sysctl', '-n', 'hw.ncpu'], quiet=0) except Exception: pass else: if re.match('^[0-9]+$', tmp): count = int(tmp) if count < 1: count = 1 elif count > 1024: count = 1024 return count
def cpu_count(): """Returns the number of processors on this machine.""" if multiprocessing is None: return 1 try: return multiprocessing.cpu_count() except NotImplementedError: pass try: return os.sysconf("SC_NPROCESSORS_CONF") except ValueError: pass gen_log.error("Could not detect number of processors; assuming 1") return 1
def _close_fds(): try: max_fd = os.sysconf("SC_OPEN_MAX") except ValueError: max_fd = 65536 for i in range(max_fd): try: os.close(i) except OSError: pass
def initgroups(uid, primaryGid): """Initializes the group access list. This is done by reading the group database /etc/group and using all groups of which C{uid} is a member. The additional group C{primaryGid} is also added to the list. If the given user is a member of more than C{NGROUPS}, arbitrary groups will be silently discarded to bring the number below that limit. """ try: # Try to get the maximum number of groups max_groups = os.sysconf("SC_NGROUPS_MAX") except: # No predefined limit max_groups = 0 username = pwd.getpwuid(uid)[0] l = [] if primaryGid is not None: l.append(primaryGid) for groupname, password, gid, userlist in grp.getgrall(): if username in userlist: l.append(gid) if len(l) == max_groups: break # No more groups, ignore any more try: _setgroups_until_success(l) except OSError, e: # We might be able to remove this code now that we # don't try to setgid/setuid even when not asked to. if e.errno == errno.EPERM: for g in getgroups(): if g not in l: raise else: raise
def cpu_count_logical(): """Return the number of logical CPUs in the system.""" try: return os.sysconf("SC_NPROCESSORS_ONLN") except ValueError: # as a second fallback we try to parse /proc/cpuinfo num = 0 with open_binary('%s/cpuinfo' % get_procfs_path()) as f: for line in f: if line.lower().startswith(b'processor'): num += 1 # unknown format (e.g. amrel/sparc architectures), see: # https://github.com/giampaolo/psutil/issues/200 # try to parse /proc/stat as a last resort if num == 0: search = re.compile('cpu\d') with open_text('%s/stat' % get_procfs_path()) as f: for line in f: line = line.split(' ')[0] if search.match(line): num += 1 if num == 0: # mimic os.cpu_count() return None return num
def virtual_memory(): # we could have done this with kstat, but imho this is good enough total = os.sysconf('SC_PHYS_PAGES') * PAGE_SIZE # note: there's no difference on Solaris free = avail = os.sysconf('SC_AVPHYS_PAGES') * PAGE_SIZE used = total - free percent = usage_percent(used, total, _round=1) return svmem(total, avail, percent, used, free)
def cpu_count_logical(): """Return the number of logical CPUs in the system.""" try: return os.sysconf("SC_NPROCESSORS_ONLN") except ValueError: # mimic os.cpu_count() behavior return None
def calculate_memory_for_sort(): """Calculate available memory for ``samtools sort`` function. If there is enough memory, no temp files are created. **Enough** is defined as at least 1G per CPU. Returns ------- sort_memory: str or None String to use directly with *-m* option in sort, or None. """ avail_memory = None if HAVE_PSUTIL == True: mem = virtual_memory() avail_memory = mem.total else: try: avail_memory = os.sysconf('SC_PAGE_SIZE') * os.sysconf('SC_PHYS_PAGES') # e.g. 4015976448 except ValueError: logging.error("If you're in Mac OS you need to have the psutil Python library.") raise SystemExit avail_cpu = multiprocessing.cpu_count() sort_memory = avail_memory / avail_cpu / 1024 ** 2 # samtools default from documentation is 768M, to be conservative # only use -m option when there is more than 1G per CPU. if sort_memory < 1024: sort_memory = None else: sort_memory = "%sG" % (int(floor(sort_memory / 1024))) return sort_memory # --------------------------------------------------------------------------------------------------
