.TH "PAPI_hl_region_end" 3 "Thu Dec 14 2023" "Version 7.1.0.0" "PAPI" \" -*- nroff -*-
.ad l
.nh
.SH NAME
PAPI_hl_region_end \- Read performance events at the end of a region and store the difference to the corresponding beginning of the region\&.  

.SH SYNOPSIS
.br
.PP
.SH "Detailed Description"
.PP 

.PP
\fBC Interface:\fP
.RS 4
#include <\fBpapi\&.h\fP> 
.br
int \fBPAPI_hl_region_end( const char* region )\fP;
.RE
.PP
\fBParameters\fP
.RS 4
\fIregion\fP -- a unique region name corresponding to \fBPAPI_hl_region_begin\fP
.RE
.PP
\fBReturn values\fP
.RS 4
\fIPAPI_OK\fP 
.br
\fIPAPI_ENOTRUN\fP -- EventSet is currently not running or could not determined\&. 
.br
\fIPAPI_ESYS\fP -- A system or C library call failed inside PAPI, see the errno variable\&. 
.br
\fIPAPI_EMISC\fP -- PAPI has been deactivated due to previous errors\&. 
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\fIPAPI_ENOMEM\fP -- Insufficient memory\&.
.RE
.PP
\fBPAPI_hl_region_end\fP reads performance events at the end of a region and stores the difference to the corresponding beginning of the region\&.
.PP
Assumes that \fBPAPI_hl_region_begin\fP was called before\&.
.PP
Note that \fBPAPI_hl_region_end\fP does not stop counting the performance events\&. Counting continues until the application terminates\&. Therefore, the programmer can also create nested regions if required\&. To stop a running high-level event set, the programmer must call \fBPAPI_hl_stop()\fP\&. It should also be noted, that a marked region is thread-local and therefore has to be in the same thread\&.
.PP
An output of the measured events is created automatically after the application exits\&. In the case of a serial, or a thread-parallel application there is only one output file\&. MPI applications would be saved in multiple files, one per MPI rank\&. The output is generated in the current directory by default\&. However, it is recommended to specify an output directory for larger measurements, especially for MPI applications via the environment variable PAPI_OUTPUT_DIRECTORY\&. In the case where measurements are performed, while there are old measurements in the same directory, PAPI will not overwrite or delete the old measurement directories\&. Instead, timestamps are added to the old directories\&.
.PP
For more convenience, the output can also be printed to stdout by setting PAPI_REPORT=1\&. This is not recommended for MPI applications as each MPI rank tries to print the output concurrently\&.
.PP
The generated measurement output can also be converted in a better readable output\&. The python script papi_hl_output_writer\&.py enhances the output by creating some derived metrics, like IPC, MFlops/s, and MFlips/s as well as real and processor time in case the corresponding PAPI events have been recorded\&. The python script can also summarize performance events over all threads and MPI ranks when using the option 'accumulate' as seen below\&.
.PP
\fBExample:\fP
.RS 4

.RE
.PP
.PP
.nf
int retval;

retval = PAPI_hl_region_begin("computation");
if ( retval != PAPI_OK )
    handle_error(1);

 //Do some computation here

retval = PAPI_hl_region_end("computation");
if ( retval != PAPI_OK )
    handle_error(1);
.fi
.PP
.PP
.PP
.nf
python papi_hl_output_writer\&.py \-\-type=accumulate

{
   "computation": {
      "Region count": 1,
      "Real time in s": 0\&.97 ,
      "CPU time in s": 0\&.98 ,
      "IPC": 1\&.41 ,
      "MFLIPS /s": 386\&.28 ,
      "MFLOPS /s": 386\&.28 ,
      "Number of ranks ": 1,
      "Number of threads ": 1,
      "Number of processes ": 1
   }
}
.fi
.PP
.PP
\fBSee also\fP
.RS 4
\fBPAPI_hl_region_begin\fP 
.PP
\fBPAPI_hl_read\fP 
.PP
\fBPAPI_hl_stop\fP 
.RE
.PP


.SH "Author"
.PP 
Generated automatically by Doxygen for PAPI from the source code\&.