1libtraceevent(3) 2================ 3 4NAME 5---- 6tep_get_page_size, tep_set_page_size, tep_get_sub_buffer_data_size, tep_get_sub_buffer_size - Get / set the size of a memory page on 7the machine, where the trace is generated 8 9SYNOPSIS 10-------- 11[verse] 12-- 13*#include <event-parse.h>* 14 15int *tep_get_page_size*(struct tep_handle pass:[*]_tep_); 16void *tep_set_page_size*(struct tep_handle pass:[*]_tep_, int _page_size_); 17int *tep_get_sub_buffer_size*(struct tep_handle pass:[*]_tep_); 18int *tep_get_sub_buffer_data_size*(struct tep_handle pass:[*]_tep_); 19int *tep_get_sub_buffer_commit_offset*(struct tep_handle pass:[*]_tep_); 20-- 21 22DESCRIPTION 23----------- 24The *tep_get_page_size()* function returns the size of a memory page on 25the machine, where the trace is generated. The _tep_ argument is trace 26event parser context. 27 28The *tep_set_page_size()* function stores in the _tep_ context the size of a 29memory page on the machine, where the trace is generated. 30The _tep_ argument is trace event parser context. 31The _page_size_ argument is the size of a memory page, in bytes. 32 33The *tep_get_sub_buffer_size()* returns the size of each "sub buffer" of the 34ring buffer. The Linux kernel ring buffer is broken up into sections called 35sub buffers. This returns the size of those buffers. 36 37The *tep_get_sub_buffer_data_size()* returns the size of just the data portion 38of the sub buffers. 39 40The *tep_get_sub_buffer_commit_offset()* returns the offset on the sub buffer 41that holds the committed portion of data. This number contains the index from 42the data portion of the sub buffer that is the end of the last element on the 43sub buffer. 44 45RETURN VALUE 46------------ 47The *tep_get_page_size()* function returns size of the memory page, in bytes. 48 49The *tep_get_sub_buffer_size()* function returns the number of bytes each sub 50buffer is made up of. 51 52The *tep_get_sub_buffer_commit_offset()* function returns the location on the 53sub buffer that contains the index of the last element. 54 55EXAMPLE 56------- 57[source,c] 58-- 59#include <unistd.h> 60#include <event-parse.h> 61... 62struct tep_handle *tep = tep_alloc(); 63... 64 int page_size = getpagesize(); 65 66 tep_set_page_size(tep, page_size); 67 68 printf("The page size for this machine is %d\n", tep_get_page_size(tep)); 69 70-- 71 72FILES 73----- 74[verse] 75-- 76*event-parse.h* 77 Header file to include in order to have access to the library APIs. 78*-ltraceevent* 79 Linker switch to add when building a program that uses the library. 80-- 81 82SEE ALSO 83-------- 84*libtraceevent*(3), *trace-cmd*(1) 85 86AUTHOR 87------ 88[verse] 89-- 90*Steven Rostedt* <[email protected]>, author of *libtraceevent*. 91*Tzvetomir Stoyanov* <[email protected]>, author of this man page. 92-- 93REPORTING BUGS 94-------------- 95Report bugs to <[email protected]> 96 97LICENSE 98------- 99libtraceevent is Free Software licensed under the GNU LGPL 2.1 100 101RESOURCES 102--------- 103https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/ 104