tests: add ioctl_period test

The various corner cases of this came up recently due to e-mail
conversation with Andreas Sandberg

CHANGES

@@ -1,3 +1,6 @@
+28 October 2013
++ Add ioctl_period test
+
 11 October 2013
 + Add tests/error_returns/e2big
 + Move non-existent test to tests/error_returns

run_tests.sh

@@ -78,6 +78,9 @@ $TESTS_DIR/ioctl/ioctl_flag_group
 echo "  + $TESTS_DIR/ioctl/ioctl_id"
 echo -n "    "
 $TESTS_DIR/ioctl/ioctl_id
+echo "  + $TESTS_DIR/ioctl/ioctl_period"
+echo -n "    "
+$TESTS_DIR/ioctl/ioctl_period
 
 echo
 echo "* Checking error returns"

tests/ioctl/Makefile

@@ -5,7 +5,8 @@ LIB = ../../lib
 
 all:	\
 	ioctl_flag_group \
-	ioctl_id
+	ioctl_id \
+	ioctl_period
 
 ###
 
@@ -51,9 +52,27 @@ ioctl_id.o:	ioctl_id.c
 	$(CC) $(CFLAGS) -c ioctl_id.c
 
 
+
+
+###
+
+ioctl_period:	ioctl_period.o $(LIB)/test_utils.o \
+					$(LIB)/perf_helpers.o \
+					$(LIB)/instructions_testcode.o
+	$(CC) $(LFLAGS) -o ioctl_period ioctl_period.o \
+				$(LIB)/test_utils.o \
+				$(LIB)/instructions_testcode.o \
+				$(LIB)/perf_helpers.o -lpthread
+
+ioctl_period.o:	ioctl_period.c
+	$(CC) $(CFLAGS) -c ioctl_period.c
+
+
+
 ####
 
 clean:	
 	rm -f *~ *.o \
 	ioctl_flag_group \
-	ioctl_id
+	ioctl_id \
+	ioctl_period

tests/ioctl/ioctl_period.c

@@ -0,0 +1,190 @@
+/* ioctl_period.c					*/
+/* Test the PERF_EVENT_IOC_PERIOD ioctl			*/
+
+/* by Vince Weaver   vincent.weaver _at_ maine.edu	*/
+
+/* Since 3.7 (3581fe0ef37) ARM behaves differently	*/
+/*	and updates the period immediately rather	*/
+/*	than after the next overflow.			*/
+
+/* This ioctl was broken until 2.6.36			*/
+/*	ad0cf3478de8677f720ee06393b3147819568d6a	*/
+/*	and always returned EFAULT			*/
+
+
+#define _GNU_SOURCE 1
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <unistd.h>
+#include <asm/unistd.h>
+#include <sys/ioctl.h>
+#include <signal.h>
+#include <fcntl.h>
+
+#include <errno.h>
+
+#include "perf_event.h"
+#include "perf_helpers.h"
+#include "test_utils.h"
+#include "instructions_testcode.h"
+
+static char test_string[]="Testing ioctl(PERF_EVENT_IOC_PERIOD)...";
+
+#define OVERFLOWS_TO_TRACK	1024
+static long long overflow_counts[OVERFLOWS_TO_TRACK];
+static int overflows=0;
+static int ioctl_errors=0;
+static int ioctl_errno=0;
+
+static void our_handler(int signum, siginfo_t *info, void *uc) {
+	int fd = info->si_fd;
+	int ret;
+	long long value;
+	int read_result;
+	long long new_period;
+
+	/* Turn off measurement */
+	ioctl(fd,PERF_EVENT_IOC_DISABLE,0);
+
+	/* Read out value */
+	read_result=read(fd,&value,sizeof(long long));
+
+	overflow_counts[overflows]=value;
+
+	/* Increment, but make sure we don't overflow */
+	overflows++;
+	if (overflows>=OVERFLOWS_TO_TRACK) {
+		overflows=OVERFLOWS_TO_TRACK-1;
+	}
+
+	if (overflows==5) {
+		new_period=100000;
+		ret=ioctl(fd, PERF_EVENT_IOC_PERIOD,&new_period);
+		if (ret<0) {
+			ioctl_errors++;
+			ioctl_errno=errno;
+		}
+	}
+
+	/* Restart for one more sample period */
+	ret=ioctl(fd, PERF_EVENT_IOC_REFRESH,1);
+
+	(void)read_result;
+}
+
+
+int main(int argc, char** argv) {
+
+	int fd[2],i;
+	int quiet;
+	int validation_errors=0;
+
+	long long diff;
+
+	struct perf_event_attr pe;
+
+	struct sigaction sa;
+
+	quiet=test_quiet();
+
+	if (!quiet) {
+		printf("This tests the PERF_EVENT_IOC_PERIOD ioctl.\n\n");
+	}
+
+	memset(&pe,0,sizeof(struct perf_event_attr));
+
+	pe.type=PERF_TYPE_HARDWARE;
+	pe.config=PERF_COUNT_HW_INSTRUCTIONS;
+	pe.disabled=1;
+	pe.exclude_kernel=1;
+	pe.exclude_hv=1;
+	pe.sample_period=10000;
+
+	fd[0]=perf_event_open(&pe,0,-1,-1,0);
+	if (fd[0]<0) {
+		fprintf(stderr,"Error opening\n");
+		exit(1);
+	}
+
+	/* Set up overflow */
+	memset(&sa, 0, sizeof(struct sigaction));
+	sa.sa_sigaction = our_handler;
+	sa.sa_flags = SA_SIGINFO;
+	if (sigaction( SIGRTMIN+2, &sa, NULL) < 0) {
+		printf("Error setting up signal handler\n");
+	}
+	fcntl(fd[0], F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
+	fcntl(fd[0], F_SETSIG, SIGRTMIN+2);
+	fcntl(fd[0], F_SETOWN,getpid());
+
+	ioctl(fd[0], PERF_EVENT_IOC_REFRESH,1);
+
+	instructions_million();
+
+	ioctl(fd[0], PERF_EVENT_IOC_DISABLE,0);
+
+	close(fd[0]);
+
+	if (!quiet) {
+		printf("Overflows:\n");
+		for(i=0;i<overflows;i++) {
+			printf("\t%d %lld\n",i,overflow_counts[i]);
+		}
+	}
+
+	if (ioctl_errors) {
+
+		if (!quiet) {
+			if (ioctl_errno==EFAULT) {
+				fprintf(stderr,"Known issue with kernels <2.6.36, PERF_IOC_PERIOD always fails due to kernel bug.\n");
+			}
+			else {
+				fprintf(stderr,"Unknown failure with PERF_EVENT_IOC_PERIOD: %s\n",strerror(errno));
+			}
+		}
+
+		test_fail(test_string);
+	}
+
+	/* validate results */
+	/* should be 10k apart for 0,1,2,3,4,5	*/
+	/* 5-6 and after should be 100k		*/
+
+	for(i=0;i<5;i++) {
+		diff=overflow_counts[i+1]-overflow_counts[i];
+
+		if ((diff>11000) || (diff<9000)) {
+			if (!quiet) {
+				fprintf(stderr,"Overflow %i-%i should have been 10,000, was %lld\n",i,i+1,diff);
+			}
+			validation_errors++;
+		}
+	}
+
+	for(i=5;i<overflows-1;i++) {
+		diff=overflow_counts[i+1]-overflow_counts[i];
+
+		if ((diff>101000) || (diff<99000)) {
+			if (!quiet) {
+				fprintf(stderr,"Overflow %i-%i should have been 100,000, was %lld\n",i,i+1,diff);
+			}
+			validation_errors++;
+		}
+	}
+
+	if (validation_errors) {
+		test_fail(test_string);
+	}
+
+	test_pass(test_string);
+
+	/* TODO: properly handle ARM post 3.7 case */
+	/* also check for case where we reset
+		overflow on running counter?
+	*/
+
+	return 0;
+}