Functions
void	translateCpuInfoLogicalProcessorsToMachine (const std::vector< CpuInfo::LogicalProcessor > &logicalProcessors, HardwareTopology::Machine *machine)
	Utlility function to renumber and translate low-level APIC info to topology. More...

HardwareTopology::SupportLevel	parseCpuInfo (HardwareTopology::Machine *machine)
	Initialize machine data from basic information in cpuinfo. More...

int	detectLogicalProcessorCount ()
	Try to detect the number of logical processors. More...

std::vector< int >	parseCpuString (const std::string &cpuString)
	Parse cpu list (integers) from string separated by commas and ranges. More...

HardwareTopology::SupportLevel	parseSysFsCpuTopology (HardwareTopology::Machine *machine, const std::string &root="", const std::vector< int > &allowedCpus={})
	Attempt to read basic topology from Linux sysfs interface. More...

std::string	findCgroupPath (const std::vector< std::string > &mountPoints, const std::vector< std::string > &subGroups, const std::string &root)
	Find the active cgroup path for the current process. More...

float	parseCgroup1CpuLimit (const std::vector< std::string > &mountPoints, const std::string &root="")
	Parse cpu limits from cgroup version 1 file system on Linux. More...

float	parseCgroup2CpuLimit (const std::vector< std::string > &mountPoints, const std::string &root="")
	Parse cpu limits from cgroup version 2 file system on Linux. More...

float	detectCpuLimit (const std::string &root="")

int	setMaxThreads (float cpuLimit, int topologyCpus, int systemCpus)

Function Documentation

int gmx::anonymous_namespace{hardwaretopology.cpp}::detectLogicalProcessorCount ( )

Try to detect the number of logical processors.

Returns: The number of hardware processing units, or 0 if it fails.

std::string gmx::anonymous_namespace{hardwaretopology.cpp}::findCgroupPath	(	const std::vector< std::string > &	mountPoints,
		const std::vector< std::string > &	subGroups,
		const std::string &	root
	)

Find the active cgroup path for the current process.

Parameters

mountPoints	List of potential mount points
subGroups	List of potential subgroup paths
root	Optional mock root for creating topologies from saved data. If provided, all paths will be relative to this mock root.

This routine will attempt to detect the path to the cgroup that's active for the present process by searching for our own process id in the cgroups.procs file in each combination of mountPoint and subGroup.

Returns: Path to the active cgroup directory, or empty string if none found.

float gmx::anonymous_namespace{hardwaretopology.cpp}::parseCgroup1CpuLimit	(	const std::vector< std::string > &	mountPoints,
		const std::string &	root = `""`
	)

Parse cpu limits from cgroup version 1 file system on Linux.

Parameters

mountPoints	Top-level mount point for cgroups1
root	Optional mock root for creating topologies from saved data. If provided, all paths will be relative to this mock root.

Returns: Allowed CPU limit. Note that this is often larger than 1, meaning the limit is larger than 1 thread.

float gmx::anonymous_namespace{hardwaretopology.cpp}::parseCgroup2CpuLimit	(	const std::vector< std::string > &	mountPoints,
		const std::string &	root = `""`
	)

Parse cpu limits from cgroup version 2 file system on Linux.

Parameters

mountPoints	Top-level mount point for cgroups2
root	Optional mock root for creating topologies from saved data. If provided, all paths will be relative to this mock root.

Returns: Allowed CPU limit. Note that this is often larger than 1, meaning the limit is larger than 1 thread.

HardwareTopology::SupportLevel gmx::anonymous_namespace{hardwaretopology.cpp}::parseCpuInfo ( HardwareTopology::Machine * machine )

Initialize machine data from basic information in cpuinfo.

Parameters

machine Machine tree structure where information will be assigned if the cpuinfo object contains topology information.

Returns: SupportLevel::Basic if topology information was found.

std::vector<int> gmx::anonymous_namespace{hardwaretopology.cpp}::parseCpuString ( const std::string & cpuString )

Parse cpu list (integers) from string separated by commas and ranges.

Parameters

cpuString String with integers in the standard linux cpulist format, i.e. integers and integer ranges (specified with dashes) separated by commas like "0,3-5,7,8,10-15". If the string is ill-formed, or If any integer is negative or the indices are not strictly increasing, we return an empty vector.

Returns: vector containing the integers specified, with ranges expanded to all entries.

HardwareTopology::SupportLevel gmx::anonymous_namespace{hardwaretopology.cpp}::parseSysFsCpuTopology	(	HardwareTopology::Machine *	machine,
		const std::string &	root = `""`,
		const std::vector< int > &	allowedCpus = `{}`
	)

Attempt to read basic topology from Linux sysfs interface.

Parameters

machine	Pointer to machine structure in topology to be populated
root	Optional path to (mock) file system root. If this is provided, all file system access will be relative to this path instead. This allows us to create mock topologies based on saved data.
allowedCpus	When creating mock topologies by setting the root parameter, we will not attempt to check if we can run on processors based on cpuset affinity masks, but you should use this parameter to provide a vector of logical (OS) processor indices on which we are allowed to run.

This is a poor man's version of the much fancier topology detection available from hwloc, but given the compilcations of modern hardware we are critically dependent on being able to understand at least how many sockets/cores/threads we have, even when Gromacs is compiled without hwloc support.

Returns: SupportLevel::Basic if topology information was found.

void gmx::anonymous_namespace{hardwaretopology.cpp}::translateCpuInfoLogicalProcessorsToMachine	(	const std::vector< CpuInfo::LogicalProcessor > &	logicalProcessors,
		HardwareTopology::Machine *	machine
	)

Utlility function to renumber and translate low-level APIC info to topology.

Parameters

logicalProcessors	Logical processor information according to the CpuInfo structure. Note that the indices refer to low-level hardware, so they will be renumbered to only consider logical cores/processing units we use.
machine	Hardware topology machine structure where result is written.

Functions

Function Documentation