.\" -*- nroff -*- .\" Copyright 2013 Los Alamos National Security, LLC. All rights reserved. .\" Copyright 2006-2008 Sun Microsystems, Inc. .\" Copyright (c) 1996 Thinking Machines Corporation .\" Copyright (c) 2010 Cisco Systems, Inc. All rights reserved. .\" $COPYRIGHT$ .TH MPI_T_pvar_get_info 3 "Sep 30, 2023" "4.1.6" "Open MPI" . .SH NAME \fBMPI_T_pvar_get_info\fP \- Query information from a performance variable . .SH SYNTAX .ft R . .SH C Syntax .nf #include int MPI_T_pvar_get_info(int \fIpvar_index\fP, char *\fIname\fP, int *\fIname_len\fP, int *\fIverbosity\fP, int *\fIvar_class\fP, MPI_Datatype *\fIdatatype\fP, MPI_T_enum *\fIenumtype\fP, char *\fIdesc\fP, int *\fIdesc_len\fP, int *\fIbind\fP, int *\fIreadonly\fP, int *\fIcontinuous\fP, int *\fIatomic\fP) .fi .SH INPUT PARAMETERS .ft R .TP 1i pvar_index Index of the performance variable to be queried. .SH INPUT/OUTPUT PARAMETERS .ft R .TP 1i name_len Length of the string and/or buffer for name. .TP 1i desc_len Length of the string and/or buffer for desc. .SH OUTPUT PARAMETERS .ft R .TP 1i name Buffer to return the string containing the name of the performance variable. .TP 1i verbosity Verbosity level of this variable. .TP 1i var_class Class of performance variable. .TP 1i datatype MPI datatype of the information stored in the performance variable. .TP 1i enumtype Optional descriptor for enumeration information. .TP 1i desc Buffer to return the string containing the description of the performance variable. .TP 1i bind Type of MPI object to which this variable must be bound. .TP 1i readonly Flag indicating whether the variable can be written/reset. .TP 1i continuous Flag indicating whether the variable can be started and stopped or is continuously active. .TP 1i atomic Flag indicating whether the variable can be atomically read and reset. . . .SH DESCRIPTION .ft R MPI_T_pvar_get_info can be used to query information from a performance variable. The function returns the verbosity, class, datatype, enumeration type, and binding of the queried control variable in the arguments \fIverbosity\fP, \fIvar_class\fP, \fIdatatype\fP, \fIenumtype\fP, and \fIbind\fP respectively. Flags indicating whether the variable is read-only, continuous, or atomic are returns in \fIreadonly\fP, \fIcontinuous\fP, and \fIatomic\fP accordingly. See MPI-3 ยง 14.3.7 for more information. See the man page for MPI_T_cvar_get_info for information on variable verbosity. .SH VARIABLE CLASS .ft R Performance variables are categorized into classes which describe their initial value, valid types, and behavior. The class returned in the \fIvar_class\fP parameter may be one of the following: .TP 2 MPI_T_PVAR_CLASS_STATE Variable represents a set of discrete states that may be described by an enumerator. Variables of this class must be represented by an MPI_INT. The starting value is the current state of the variable. .TP 2 MPI_T_PVAR_CLASS_LEVEL Variable represents the current utilization level of a resource. Variables of this class must be represented by an MPI_UNSIGNED, MPI_UNSIGNED_LONG, MPI_UNSIGNED_LONG_LONG, or MPI_DOUBLE. The starting value is the current utilization level of the resource. .TP 2 MPI_T_PVAR_CLASS_SIZE Variable represents the fixed size of a resource. Variables of this class are represented by an MPI_UNSIGNED, MPI_UNSIGNED_LONG, MPI_UNSIGNED_LONG_LONG, or MPI_DOUBLE. The starting value is the current size of the resource. .TP 2 MPI_T_PVAR_CLASS_PERCENTAGE Variable represents the current precentage utilization level of a resource. Variables of this class are represented by an MPI_DOUBLE. The starting value is the current percentage utilization of the resource. .TP 2 MPI_T_PVAR_CLASS_HIGHWATERMARK Variable represents the high watermark of the utilization of a resource. Variables of this class are represented by an MPI_UNSIGNED, MPI_UNSIGNED_LONG, MPI_UNSIGNED_LONG_LONG, or MPI_DOUBLE. The starting value is the current utilization of the resource. .TP 2 MPI_T_PVAR_CLASS_HIGHWATERMARK Variable represents the low watermark of the utilization of a resource. Variables of this class are represented by an MPI_UNSIGNED, MPI_UNSIGNED_LONG, MPI_UNSIGNED_LONG_LONG, or MPI_DOUBLE. The starting value is the current utilization of the resource. .TP 2 MPI_T_PVAR_CLASS_COUNTER Variable represents a count of the number of occurrences of a specific event. Variables of this class are represented by an MPI_UNSIGNED, MPI_UNSIGNED_LONG, or MPI_UNSIGNED_LONG_LONG. The starting value is 0. .TP 2 MPI_T_PVAR_CLASS_COUNTER Variable represents an aggregated value that represents a sum of arguments processed during a specific event. Variables of this class are represented by an MPI_UNSIGNED, MPI_UNSIGNED_LONG, MPI_UNSIGNED_LONG_LONG, or MPI_DOUBLE. The starting value is 0. .TP 2 MPI_T_PVAR_CLASS_TIMER Variable represents the aggregated time spent by the MPI implementation while processing an event, type of event, or section of code. Variables of this class are represented by an MPI_UNSIGNED, MPI_UNSIGNED_LONG, MPI_UNSIGNED_LONG_LONG, or MPI_DOUBLE. If the variable is represented by an MPI_DOUBLE the units will be the same as those used by MPI_Wtime(). The starting value is 0. .TP 2 MPI_T_PVAR_CLASS_GENERIC Variable does not fit into any other class. Can by represented by an type supported by the MPI tool information interface (see DATATYPE). Starting value is variable specific. For more information see MPI-3 \[char167] 14.3.7. .SH DATATYPE .ft R The datatype returned by MPI_T_pvar_get_info is restricted to one of the following datatypes: MPI_INT, MPI_UNSIGNED, MPI_UNSIGNED_LONG, MPI_UNSIGNED_LONG_LONG, MPI_COUNT, MPI_CHAR, and MPI_DOUBLE. For more information on datatypes in the MPI Tool information interface see MPI-3 \[char167] 14.3.5. .SH BINDING .ft R Performance variables may be bound to an MPI object. The binding returned in the \fIbind\fP parameter may be one of the following: .TP 1i MPI_T_BIND_NO_OBJECT No object .TP 1i MPI_T_BIND_MPI_COMM MPI communicator .TP 1i MPI_T_BIND_MPI_DATATYPE MPI datatype .TP 1i MPI_T_BIND_MPI_ERRHANDLER MPI error handler .TP 1i MPI_T_BIND_MPI_FILE MPI file handle .TP 1i MPI_T_BIND_MPI_GROUP MPI group .TP 1i MPI_T_BIND_MPI_OP MPI reduction operator .TP 1i MPI_T_BIND_MPI_REQUEST MPI request .TP 1i MPI_T_BIND_MPI_WIN MPI window for one-sided communication .TP 1i MPI_T_BIND_MPI_MESSAGE MPI message object .TP 1i MPI_T_BIND_MPI_INFO MPI info object For more information see MPI-3 \[char167] 14.3.2. .SH NOTES .ft R This MPI tool interface function returns two strings. This function takes two argument for each string: a buffer to store the string, and a length which must initially specify the size of the buffer. If the length passed is n then this function will copy at most n - 1 characters of the string into the corresponding buffer and set the length to the number of characters copied - 1. If the length argument is NULL or the value specified in the length is 0 the corresponding string buffer is ignored and the string is not returned. For more information see MPI-3 \[char167] 14.3.3. .SH ERRORS .ft R MPI_T_pvar_get_info() will fail if: .TP 1i [MPI_T_ERR_NOT_INITIALIZED] The MPI Tools interface not initialized .TP 1i [MPI_T_ERR_INVALID_INDEX] The performance variable index is invalid . .SH SEE ALSO .ft R .nf MPI_T_cvar_get_info