From 35483cc4938e33c6e76f475a7346bb91a4082baa Mon Sep 17 00:00:00 2001
From: Dr-Noob <peibolms@gmail.com>
Date: Fri, 16 Feb 2024 23:54:08 +0100
Subject: [PATCH] [v1.05] Improve error reporting due to perf_event_paranoid
 issues

---
 src/common/freq.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/common/freq.c b/src/common/freq.c
index 60b33cb..41c8dfe 100644
--- a/src/common/freq.c
+++ b/src/common/freq.c
@@ -45,10 +45,6 @@ int64_t measure_max_frequency(uint32_t core) {
     return -1;
   }
 
-  const char* frequency_banner = "cpufetch is measuring the max frequency...";
-  printf("%s", frequency_banner);
-  fflush(stdout);
-
   clockid_t clock = CLOCK_PROCESS_CPUTIME_ID;
 
   struct perf_event_attr pe;
@@ -63,7 +59,7 @@ int64_t measure_max_frequency(uint32_t core) {
 #elif ARCH_ARM
   // TODO
   nop_function = nop_function_arm;
-#endif  
+#endif
 
   memset(&pe, 0, sizeof(struct perf_event_attr));
   pe.type = PERF_TYPE_HARDWARE;
@@ -76,9 +72,17 @@ int64_t measure_max_frequency(uint32_t core) {
   fd = perf_event_open(&pe, pid, core, -1, 0);
   if (fd == -1) {
     perror("perf_event_open");
+    if (errno == EPERM || errno == EACCES) {
+      printf("You may not have permission to collect stats.\n");
+      printf("Consider tweaking /proc/sys/kernel/perf_event_paranoid or running as root.\n");
+    }
     return -1;
   }
 
+  const char* frequency_banner = "cpufetch is measuring the max frequency...";
+  printf("%s", frequency_banner);
+  fflush(stdout);
+
   uint64_t iters = 10000000;
   struct timespec start, end;
   if (clock_gettime(clock, &start) == -1) {