libbpf-tools/hardirqs: add --cpu/-s for hardirqs

Signed-off-by: Dantezy <[email protected]>
iovisor · Sep 14, 2024 · 51dc102 · 51dc102
1 parent 7466f69
commit 51dc102
Show file tree

Hide file tree

Showing 2 changed files with 52 additions and 24 deletions.
diff --git a/libbpf-tools/hardirqs.bpf.c b/libbpf-tools/hardirqs.bpf.c
@@ -14,6 +14,7 @@ const volatile bool filter_cg = false;
 const volatile bool targ_dist = false;
 const volatile bool targ_ns = false;
 const volatile bool do_count = false;
+const volatile bool targ_cpu = -1;
 
 struct {
 	__uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
@@ -38,12 +39,21 @@ struct {
 
 static struct info zero;
 
+static __always_inline bool is_target_cpu() {
+  if (targ_cpu < 0)
+    return true;
+
+  return (u32)targ_cpu == bpf_get_smp_processor_id();
+}
+
 static int handle_entry(int irq, struct irqaction *action)
 {
 	if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
 		return 0;
+        if (!is_target_cpu())
+          return 0;
 
-	if (do_count) {
+        if (do_count) {
 		struct irq_key key = {};
 		struct info *info;
 
@@ -76,7 +86,10 @@ static int handle_exit(int irq, struct irqaction *action)
 	if (filter_cg && !bpf_current_task_under_cgroup(&cgroup_map, 0))
 		return 0;
 
-	tsp = bpf_map_lookup_elem(&start, &key);
+        if (!is_target_cpu())
+          return 0;
+
+        tsp = bpf_map_lookup_elem(&start, &key);
 	if (!tsp)
 		return 0;
 

diff --git a/libbpf-tools/hardirqs.c b/libbpf-tools/hardirqs.c
@@ -27,9 +27,11 @@ struct env {
 	bool verbose;
 	char *cgroupspath;
 	bool cg;
+        int targ_cpu;
 } env = {
-	.interval = 99999999,
-	.times = 99999999,
+    .interval = 99999999,
+    .times = 99999999,
+    .targ_cpu = -1,
 };
 
 static volatile bool exiting;
@@ -38,26 +40,29 @@ const char *argp_program_version = "hardirqs 0.1";
 const char *argp_program_bug_address =
 	"https://github.com/iovisor/bcc/tree/master/libbpf-tools";
 const char argp_program_doc[] =
-"Summarize hard irq event time as histograms.\n"
-"\n"
-"USAGE: hardirqs [--help] [-T] [-N] [-d] [interval] [count] [-c CG]\n"
-"\n"
-"EXAMPLES:\n"
-"    hardirqs            # sum hard irq event time\n"
-"    hardirqs -d         # show hard irq event time as histograms\n"
-"    hardirqs 1 10       # print 1 second summaries, 10 times\n"
-"    hardirqs -c CG      # Trace process under cgroupsPath CG\n"
-"    hardirqs -NT 1      # 1s summaries, nanoseconds, and timestamps\n";
+    "Summarize hard irq event time as histograms.\n"
+    "\n"
+    "USAGE: hardirqs [--help] [-T] [-N] [-d] [interval] [count] [-c CG]\n"
+    "\n"
+    "EXAMPLES:\n"
+    "    hardirqs            # sum hard irq event time\n"
+    "    hardirqs -d         # show hard irq event time as histograms\n"
+    "    hardirqs 1 10       # print 1 second summaries, 10 times\n"
+    "    hardirqs -c CG      # Trace process under cgroupsPath CG\n"
+    "    hardirqs --cpu 1    # only stat irq on cpu 1\n"
+    "    hardirqs -NT 1      # 1s summaries, nanoseconds, and timestamps\n";
 
 static const struct argp_option opts[] = {
-	{ "count", 'C', NULL, 0, "Show event counts instead of timing", 0 },
-	{ "distributed", 'd', NULL, 0, "Show distributions as histograms", 0 },
-	{ "cgroup", 'c', "/sys/fs/cgroup/unified", 0, "Trace process in cgroup path", 0 },
-	{ "timestamp", 'T', NULL, 0, "Include timestamp on output", 0 },
-	{ "nanoseconds", 'N', NULL, 0, "Output in nanoseconds", 0 },
-	{ "verbose", 'v', NULL, 0, "Verbose debug output", 0 },
-	{ NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help", 0 },
-	{},
+    {"count", 'C', NULL, 0, "Show event counts instead of timing", 0},
+    {"distributed", 'd', NULL, 0, "Show distributions as histograms", 0},
+    {"cgroup", 'c', "/sys/fs/cgroup/unified", 0, "Trace process in cgroup path",
+     0},
+    {"cpu", 's', "CPU", 0, "Only stat irq on selected cpu", 0},
+    {"timestamp", 'T', NULL, 0, "Include timestamp on output", 0},
+    {"nanoseconds", 'N', NULL, 0, "Output in nanoseconds", 0},
+    {"verbose", 'v', NULL, 0, "Verbose debug output", 0},
+    {NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help", 0},
+    {},
 };
 
 static error_t parse_arg(int key, char *arg, struct argp_state *state)
@@ -77,7 +82,16 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
 	case 'C':
 		env.count = true;
 		break;
-	case 'c':
+        case 's':
+          errno = 0;
+          long c = strtol(arg, NULL, 10);
+          if (errno || c < 0) {
+            fprintf(stderr, "invalid cpu: %s\n", arg);
+            argp_usage(state);
+          }
+          env.targ_cpu = (int)c;
+          break;
+        case 'c':
 		env.cgroupspath = arg;
 		env.cg = true;
 		break;
@@ -218,8 +232,9 @@ int main(int argc, char **argv)
 
 	obj->rodata->filter_cg = env.cg;
 	obj->rodata->do_count = env.count;
+        obj->rodata->targ_cpu = env.targ_cpu;
 
-	/* initialize global data (filtering options) */
+        /* initialize global data (filtering options) */
 	if (!env.count) {
 		obj->rodata->targ_dist = env.distributed;
 		obj->rodata->targ_ns = env.nanoseconds;