Add multiplexing test

This checks if multiplexing works.  Prior to 2.6.34 this
did not work as expected.

CHANGES

@@ -1,3 +1,6 @@
+20 August 2012
++ Add multiplexing test
+
 16 August 2012
 + Add reset_leader test
 

bugs/Makefile

@@ -3,11 +3,13 @@ CFLAGS = -Wall -O2 -I../include
 LFLAGS =
 
 all:	\
-	read_group_attached \
-	check_schedulability \
+	check_multiplexing \
 	check_papi_multiplexing \
+	check_schedulability \
+	nmi_watchdog_group_leader \
+	read_group_attached \
 	sync_read_required \
-	nmi_watchdog_group_leader
+
 
 #
 
@@ -62,6 +64,21 @@ check_papi_multiplexing:	check_papi_multiplexing.o \
 check_papi_multiplexing.o:	check_papi_multiplexing.c
 	$(CC) $(CFLAGS) -c check_papi_multiplexing.c
 
+###	
+
+check_multiplexing:	check_multiplexing.o \
+				../lib/perf_helpers.o \
+				../lib/test_utils.o \
+				../lib/instructions_testcode.o
+	$(CC) $(LFLAGS) -o check_multiplexing check_multiplexing.o \
+				../lib/perf_helpers.o \
+				../lib/test_utils.o \
+				../lib/instructions_testcode.o
+
+check_multiplexing.o:	check_multiplexing.c
+	$(CC) $(CFLAGS) -c check_multiplexing.c
+
+
 ###
 
 sync_read_required:	sync_read_required.o \
@@ -92,10 +109,12 @@ nmi_watchdog_group_leader.o:	nmi_watchdog_group_leader.c
 
 clean:	
 	rm -f *~ *.o \
-	read_group_attached \
-	check_schedulability \
+	check_multiplexing \
 	check_papi_multiplexing \
+	check_schedulability \
+	nmi_watchdog_group_leader \
+	read_group_attached \
 	sync_read_required \
-	nmi_watchdog_group_leader
+
 
 

bugs/check_multiplexing.c

@@ -0,0 +1,205 @@
+/* check_multiplexing.c  */
+/* by Vince Weaver   vweaver1 _at_ eecs.utk.edu */
+
+/* Prior to 2.6.34 perf_event multiplexing was unreliable */
+/* The values were not updated properly.                  */
+/* This was probably fixed by                             */
+/* 45e16a6834b6af098702e5ea6c9a40de42ff77d8               */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <unistd.h>
+#include <errno.h>
+
+#include <sys/mman.h>
+
+#include <sys/ioctl.h>
+#include <asm/unistd.h>
+
+#include "perf_event.h"
+#include "test_utils.h"
+#include "perf_helpers.h"
+#include "instructions_testcode.h"
+
+#define NUM_EVENTS 10
+
+int fd[NUM_EVENTS];
+long long events[NUM_EVENTS]={
+   PERF_COUNT_HW_CPU_CYCLES,
+   PERF_COUNT_HW_INSTRUCTIONS,
+   PERF_COUNT_HW_CPU_CYCLES,
+   PERF_COUNT_HW_INSTRUCTIONS,
+   PERF_COUNT_HW_CPU_CYCLES,
+   PERF_COUNT_HW_INSTRUCTIONS,
+   PERF_COUNT_HW_CPU_CYCLES,
+   PERF_COUNT_HW_INSTRUCTIONS,
+   PERF_COUNT_HW_CPU_CYCLES,
+   PERF_COUNT_HW_INSTRUCTIONS,
+};
+
+long long base_results[NUM_EVENTS][3];
+long long mpx_results[NUM_EVENTS][3];
+long long scaled_results[NUM_EVENTS];
+long long scale;
+double error[NUM_EVENTS];
+int bad_error=0;
+
+int test_routine(void) {
+
+  int i,result;
+
+  for(i=0;i<500;i++) {
+     result=instructions_million();
+  }
+
+  return result;
+}
+
+int main(int argc, char** argv) {
+
+   int ret,quiet,i;
+
+   struct perf_event_attr pe;
+
+   char test_string[]="Testing if multiplexing works...";
+
+   quiet=test_quiet();
+
+   if (!quiet) {
+      printf("Before 2.6.34 the values returned when multiplexing\n");
+      printf("  were not reliable and could result in wrong results.\n");
+   }
+
+   /* setup all 10 counters */
+
+   fd[0]=-1;
+   for(i=0;i<NUM_EVENTS;i++) {
+
+      memset(&pe,0,sizeof(struct perf_event_attr));
+      pe.type=PERF_TYPE_HARDWARE;
+      pe.size=sizeof(struct perf_event_attr);
+      pe.config=events[i];
+      pe.disabled=1;
+      pe.exclude_kernel=1;
+      pe.exclude_hv=1;
+      pe.read_format=PERF_FORMAT_TOTAL_TIME_ENABLED | 
+	             PERF_FORMAT_TOTAL_TIME_RUNNING;
+
+      arch_adjust_domain(&pe,quiet);
+
+      fd[i]=perf_event_open(&pe,0,-1,-1,0);
+      if (fd[i]<0) {
+	 fprintf(stderr,"Failed adding mpx event %d %s\n",i,strerror(errno));
+         test_fail(test_string);
+	 return -1;
+      }
+   }
+
+   /*************************************************/
+   /* Collect results for each counter individually */
+   /*************************************************/
+
+   for(i=0;i<NUM_EVENTS;i++) {
+      ret=ioctl(fd[i], PERF_EVENT_IOC_ENABLE,0);
+      if (ret<0) {
+	 fprintf(stderr,"Error starting event %d\n",i);
+      }
+
+      test_routine();
+
+      ret=ioctl(fd[i], PERF_EVENT_IOC_DISABLE,0);
+      if (ret<0) {
+	 fprintf(stderr,"Error stopping event %d\n",i);
+      }
+
+      ret=read(fd[i],&base_results[i],3*sizeof(long long));
+      if (ret<3*sizeof(long long)) {
+	fprintf(stderr,"Event %d unexpected read size %d\n",i,ret);
+        test_fail(test_string);
+      }
+      if (base_results[i][1]!=base_results[i][2]) {
+	fprintf(stderr,"Event %d running %lld != %lld base\n",
+		i,base_results[i][1],base_results[i][2]);
+	test_fail(test_string);
+      }
+
+   }
+
+   /*************************************************/
+   /* Collect multiplexed results                   */
+   /*************************************************/
+
+   for(i=0;i<NUM_EVENTS;i++) {
+      ret=ioctl(fd[i], PERF_EVENT_IOC_RESET,0);
+      if (ret<0) {
+	 fprintf(stderr,"Error starting event %d\n",i);
+      }
+   }
+
+   for(i=0;i<NUM_EVENTS;i++) {
+      ret=ioctl(fd[i], PERF_EVENT_IOC_ENABLE,0);
+      if (ret<0) {
+	 fprintf(stderr,"Error starting event %d\n",i);
+      }
+   }
+
+
+   test_routine();
+
+   for(i=0;i<NUM_EVENTS;i++) {
+      ret=ioctl(fd[i], PERF_EVENT_IOC_DISABLE,0);
+      if (ret<0) {
+	 fprintf(stderr,"Error stopping event %d\n",i);
+      }
+   }
+
+
+   for(i=0;i<NUM_EVENTS;i++) {
+      ret=read(fd[i],&mpx_results[i],3*sizeof(long long));
+      if (ret<3*sizeof(long long)) {
+	fprintf(stderr,"Event %d unexpected read size %d\n",i,ret);
+        test_fail(test_string);
+      }
+
+      scale = (mpx_results[i][1] * 100LL) / mpx_results[i][2];
+      scale = scale * mpx_results[i][0];
+      scale = scale / 100LL;
+      scaled_results[i] = scale;
+
+   }
+
+   for(i=0;i<NUM_EVENTS;i++) {
+     error[i]=((double)base_results[i][0] - (double)scaled_results[i])/
+       (double)base_results[i][0];
+     error[i]*=100.0;
+     if ((error[i]>10.0) || (error[i]<-10.0)) {
+        bad_error++;
+     }
+
+   }
+
+   if (!quiet) {
+      printf("Event\tTotalCount\tRawCount\tScaledCount\tError\n");
+      for(i=0;i<NUM_EVENTS;i++) {
+
+         printf("%d\t%lld\t%lld\t%lld\t%.2f%%\n",i,
+	    base_results[i][0],mpx_results[i][0],scaled_results[i],
+	    error[i]);
+
+      }
+   }
+
+   if (bad_error>0) {
+      fprintf(stderr,"Error on %d events is too high.\n",bad_error);
+      test_fail(test_string);
+   }
+
+
+   test_pass(test_string);
+
+   return 0;
+}
+

run_tests.sh

@@ -37,6 +37,7 @@ echo "* Checking bugs that PAPI has to work around"
 ./bugs/check_schedulability
 ./bugs/check_papi_multiplexing
 ./bugs/nmi_watchdog_group_leader
+./bugs/check_multiplexing
 
 echo
 echo "* Checking bugs that can silently produce wrong results"