Hi all,
I was trying to track down when and where the performance_counter
syscalls were added to the Linux kernel, and it appears to have been
2.6.31. The current testcases run and fail on all architectures,
without returning -1 and setting errno == ENOSYS. So I'm proposing the
following change, but of course wondering whether or not it makes
sense:
1. Block off testcases for kernel versions <2.6.31.
2. Make asserts into more graceful errors.
3. Convert tst_resm + tst_exit into tst_brkm's.
4. Convert hardcoded 8's into sizeof(unsigned long long)'s, or
sizeof() for the equivalent variable under inspection.
Signed-off-by: Garrett Cooper <[email protected]>
Index: ./performance_counters/performance_counter01.c
===================================================================
RCS file:
/cvsroot/ltp/ltp/testcases/kernel/performance_counters/performance_counter01.c,v
retrieving revision 1.5
diff -u -r1.5 performance_counter01.c
--- ./performance_counters/performance_counter01.c 27 Nov 2009
08:15:35 -0000 1.5
+++ ./performance_counters/performance_counter01.c 27 Nov 2009
08:31:33 -0000
@@ -62,32 +62,57 @@
int
main(void) {
+
unsigned long long count1, count2;
int fd1, fd2, ret;
+
+ /*
+ * Kernel performance counters weren't available until 2.6.31 --
+ * http://lwn.net/Articles/311850/
+ *
+ * The syscalls don't return -1 // errno == ENOSYS either. Weird.
+ */
+ if (tst_kvercmp(2, 6, 31) < 0) {
+ tst_brkm(TCONF, cleanup,
+ "performance_counter support only available in "
+ "2.6.31+");
+ }
fd1 = syscall(__NR_perf_counter_open,
PERF_COUNT_INSTRUCTIONS, 0, 0, 0, -1);
if (fd1 < 0) {
- tst_resm(TBROK | TERRNO,
+ tst_brkm(TBROK | TERRNO, cleanup,
"Failed to create PERF_COUNT_INSTRUCTIONS fd");
- tst_exit();
}
fd2 = syscall(__NR_perf_counter_open,
PERF_COUNT_CACHE_MISSES, 0, 0, 0, -1);
if (fd2 < 0) {
- tst_resm(TBROK | TERRNO,
+ tst_brkm(TBROK | TERRNO, cleanup,
"Failed to create PERF_COUNT_CACHE_MISSES fd");
- tst_exit();
}
- for (;;) {
+ do {
+
ret = read(fd1, &count1, sizeof(count1));
- assert(ret == 8);
- ret = read(fd2, &count2, sizeof(count2));
- assert(ret == 8);
- printf("counter1 value: %Ld instructions\n", count1);
- printf("counter2 value: %Ld cachemisses\n", count2);
- sleep(1);
- }
- return 0;
+
+ if (ret == sizeof(count1)) {
+
+ ret = read(fd2, &count2, sizeof(count2));
+
+ if (ret == sizeof(count2)) {
+ tst_resm(TINFO,
+ "counter1 value: %Ld instructions",
+ count1);
+ tst_resm(TINFO,
+ "counter2 value: %Ld cachemisses",
+ count2);
+ sleep(1);
+ }
+
+ }
+
+ } while (ret == sizeof(unsigned long long));
+
+ tst_exit();
+
}
Index: ./performance_counters/performance_counter02.c
===================================================================
RCS file:
/cvsroot/ltp/ltp/testcases/kernel/performance_counters/performance_counter02.c,v
retrieving revision 1.4
diff -u -r1.4 performance_counter02.c
--- ./performance_counters/performance_counter02.c 27 Nov 2009
08:15:35 -0000 1.4
+++ ./performance_counters/performance_counter02.c 27 Nov 2009
08:31:33 -0000
@@ -154,6 +154,18 @@
int verbose = 0;
double ratio;
+ /*
+ * Kernel performance counters weren't available until 2.6.31 --
+ * http://lwn.net/Articles/311850/
+ *
+ * The syscalls don't return -1 // errno == ENOSYS either. Weird.
+ */
+ if (tst_kvercmp(2, 6, 31) < 0) {
+ tst_brkm(TCONF, cleanup,
+ "performance_counter support only available in "
+ "2.6.31+");
+ }
+
nhw = 8;
while ((i = getopt(ac, av, "c:v")) != -1) {
switch (i) {
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