PAPI 7.1.0.0
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low-level.c
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1/* This examples show the essentials in using the PAPI low-level
2 interface. The program consists of 3 examples where the work
3 done over some work-loops. The example tries to illustrate
4 some simple mistakes that are easily made and how a correct
5 code would accomplish the same thing.
6
7 Example 1: The total count over two work loops (Loops 1 and 2)
8 are supposed to be measured. Due to a mis-understanding of the
9 semantics of the API the total count gets wrong.
10 The example also illustrates that it is legal to read both
11 running and stopped counters.
12
13 Example 2: The total count over two work loops (Loops 1 and 3)
14 is supposed to be measured while discarding the counts made in
15 loop 2. Instead the counts in loop1 are counted twice and the
16 counts in loop2 are added to the total number of counts.
17
18 Example 3: One correct way of accomplishing the result aimed for
19 in example 2.
20*/
21
22#include <stdio.h>
23#include <stdlib.h>
24
25#include "papi.h"
26#include "papi_test.h"
27
28#include "do_loops.h"
29
30#define NUM_EVENTS 2
31
32int
33main( int argc, char **argv )
34{
35 int retval;
36 long long values[NUM_EVENTS], dummyvalues[NUM_EVENTS];
37 int Events[NUM_EVENTS];
38 int EventSet = PAPI_NULL;
39 int quiet;
40
41 /* Set TESTS_QUIET variable */
42 quiet=tests_quiet( argc, argv );
43
44 retval = PAPI_library_init( PAPI_VER_CURRENT );
45 if (retval != PAPI_VER_CURRENT ) {
46 test_fail( __FILE__, __LINE__, "PAPI_library_init", retval );
47 }
48
49 /* query and set up the right events to monitor */
50 if ( PAPI_query_event( PAPI_FP_INS ) == PAPI_OK ) {
51 Events[0] = PAPI_FP_INS;
52 Events[1] = PAPI_TOT_CYC;
53 } else {
54 Events[0] = PAPI_TOT_INS;
55 Events[1] = PAPI_TOT_CYC;
56 }
57
58 retval = PAPI_create_eventset( &EventSet );
59 if (retval != PAPI_OK ) {
60 test_fail( __FILE__, __LINE__, "PAPI_create_eventset", retval );
61 }
62
63 retval = PAPI_add_events( EventSet, ( int * ) Events, NUM_EVENTS );
64 if (retval < PAPI_OK ) {
65 if (!quiet) printf("Trouble adding events\n");
66 test_skip( __FILE__, __LINE__, "PAPI_add_events", retval );
67 }
68
69 if ( !quiet ) {
70 printf( "\n Incorrect usage of read and accum.\n" );
71 printf( " Some cycles are counted twice\n" );
72 }
73 if ( ( retval = PAPI_start( EventSet ) ) != PAPI_OK )
74 test_fail( __FILE__, __LINE__, "PAPI_start", retval );
75
76 /* Loop 1 */
77 do_flops( NUM_FLOPS );
78
79 if ( ( retval = PAPI_read( EventSet, values ) ) != PAPI_OK )
80 test_fail( __FILE__, __LINE__, "PAPI_read", retval );
81
82 if ( !quiet )
83 printf( TWO12, values[0], values[1], "(Counters continuing...)\n" );
84
85 /* Loop 2 */
86 do_flops( NUM_FLOPS );
87
88 /* Using PAPI_accum here is incorrect. The result is that Loop 1 *
89 * is being counted twice */
90 if ( ( retval = PAPI_accum( EventSet, values ) ) != PAPI_OK )
91 test_fail( __FILE__, __LINE__, "PAPI_accum", retval );
92
93 if ( !quiet )
94 printf( TWO12, values[0], values[1], "(Counters being accumulated)\n" );
95
96 /* Loop 3 */
97 do_flops( NUM_FLOPS );
98
99 if ( ( retval = PAPI_stop( EventSet, dummyvalues ) ) != PAPI_OK )
100 test_fail( __FILE__, __LINE__, "PAPI_stop", retval );
101
102 if ( ( retval = PAPI_read( EventSet, dummyvalues ) ) != PAPI_OK )
103 test_fail( __FILE__, __LINE__, "PAPI_read", retval );
104
105 if ( !quiet ) {
106 printf( TWO12, dummyvalues[0], dummyvalues[1],
107 "(Reading stopped counters)\n" );
108
109 printf( TWO12, values[0], values[1], "" );
110
111 printf( "\n Incorrect usage of read and accum.\n" );
112 printf( " Another incorrect use\n" );
113 }
114 if ( ( retval = PAPI_start( EventSet ) ) != PAPI_OK )
115 test_fail( __FILE__, __LINE__, "PAPI_start", retval );
116
117 /* Loop 1 */
118 do_flops( NUM_FLOPS );
119
120 if ( ( retval = PAPI_read( EventSet, values ) ) != PAPI_OK )
121 test_fail( __FILE__, __LINE__, "PAPI_read", retval );
122
123 if ( !quiet )
124 printf( TWO12, values[0], values[1], "(Counters continuing...)\n" );
125
126 /* Loop 2 */
127 /* Code that should not be counted */
128 do_flops( NUM_FLOPS );
129
130 if ( ( retval = PAPI_read( EventSet, dummyvalues ) ) != PAPI_OK )
131 test_fail( __FILE__, __LINE__, "PAPI_read", retval );
132
133 if ( !quiet )
134 printf( TWO12, dummyvalues[0], dummyvalues[1],
135 "(Intermediate counts...)\n" );
136
137 /* Loop 3 */
138 do_flops( NUM_FLOPS );
139
140 /* Since PAPI_read does not reset the counters it's use above after *
141 * loop 2 is incorrect. Instead Loop1 will in effect be counted twice. *
142 * and the counts in loop 2 are included in the total counts */
143 if ( ( retval = PAPI_accum( EventSet, values ) ) != PAPI_OK )
144 test_fail( __FILE__, __LINE__, "PAPI_accum", retval );
145 if ( !quiet )
146 printf( TWO12, values[0], values[1], "" );
147
148 if ( ( retval = PAPI_stop( EventSet, dummyvalues ) ) != PAPI_OK )
149 test_fail( __FILE__, __LINE__, "PAPI_stop", retval );
150
151 if ( !quiet ) {
152 printf( "\n Correct usage of read and accum.\n" );
153 printf( " PAPI_reset and PAPI_accum used to skip counting\n" );
154 printf( " a section of the code.\n" );
155 }
156 if ( ( retval = PAPI_start( EventSet ) ) != PAPI_OK )
157 test_fail( __FILE__, __LINE__, "PAPI_start", retval );
158
159 do_flops( NUM_FLOPS );
160
161 if ( ( retval = PAPI_read( EventSet, values ) ) != PAPI_OK )
162 test_fail( __FILE__, __LINE__, "PAPI_read", retval );
163 if ( !quiet )
164 printf( TWO12, values[0], values[1], "(Counters continuing)\n" );
165
166 /* Code that should not be counted */
167 do_flops( NUM_FLOPS );
168
169 if ( ( retval = PAPI_reset( EventSet ) ) != PAPI_OK )
170 test_fail( __FILE__, __LINE__, "PAPI_reset", retval );
171
172 if ( !quiet )
173 printf( "%12s %12s (Counters reset)\n", "", "" );
174
175 do_flops( NUM_FLOPS );
176
177 if ( ( retval = PAPI_accum( EventSet, values ) ) != PAPI_OK )
178 test_fail( __FILE__, __LINE__, "PAPI_accum", retval );
179
180 if ( !quiet )
181 printf( TWO12, values[0], values[1], "" );
182
183 if ( !quiet ) {
184 printf( "----------------------------------\n" );
185 printf( "Verification: The last line in each experiment should be\n" );
186 printf( "approximately twice the value of the first line.\n" );
187 printf
188 ( "The third case illustrates one possible way to accomplish this.\n" );
189 }
190 test_pass( __FILE__ );
191
192 return 0;
193}
PAPI_accum
Accumulate and reset counters in an EventSet.
PAPI_add_events
add multiple PAPI presets or native hardware events to an event set
PAPI_create_eventset
Create a new empty PAPI EventSet.
PAPI_library_init
initialize the PAPI library.
PAPI_query_event
Query if PAPI event exists.
PAPI_read
Read hardware counters from an event set.
PAPI_reset
Reset the hardware event counts in an event set.
PAPI_start
Start counting hardware events in an event set.
PAPI_stop
Stop counting hardware events in an event set.
do_loops.h
PAPI_VER_CURRENT
#define PAPI_VER_CURRENT
Definition: f90papi.h:54
PAPI_OK
#define PAPI_OK
Definition: f90papi.h:73
PAPI_NULL
#define PAPI_NULL
Definition: f90papi.h:78
PAPI_TOT_CYC
#define PAPI_TOT_CYC
Definition: f90papi.h:308
PAPI_FP_INS
#define PAPI_FP_INS
Definition: f90papi.h:366
PAPI_TOT_INS
#define PAPI_TOT_INS
Definition: f90papi.h:317
EventSet
static int EventSet
Definition: init_fini.c:8
values
static long long values[NUM_EVENTS]
Definition: init_fini.c:10
NUM_EVENTS
#define NUM_EVENTS
Definition: low-level.c:30
do_flops
void do_flops(int n)
Definition: multiplex.c:23
dummyvalues
long long dummyvalues[2]
Definition: overflow_one_and_read.c:35
papi.h
Return codes and api definitions.
papi_test.h
tests_quiet
int tests_quiet(int argc, char **argv)
Definition: test_utils.c:376
TWO12
#define TWO12
Definition: papi_test.h:103
test_fail
void PAPI_NORETURN test_fail(const char *file, int line, const char *call, int retval)
Definition: test_utils.c:491
test_pass
void PAPI_NORETURN test_pass(const char *filename)
Definition: test_utils.c:432
test_skip
void PAPI_NORETURN test_skip(const char *file, int line, const char *call, int retval)
Definition: test_utils.c:584
main
int main()
Definition: pernode.c:20
quiet
int quiet
Definition: rapl_overflow.c:19
NUM_FLOPS
#define NUM_FLOPS
Definition: sdsc-mpx.c:24
retval
int retval
Definition: zero_fork.c:53