Merge pull request iovisor#2804 from netedwardwu/master

softirqs: Combined CPU as part of the key is necessary to avoid amiss…

tools/softirqs.py

@@ -54,6 +54,11 @@
 bpf_text = """
 #include <uapi/linux/ptrace.h>
 
+typedef struct entry_key {
+ u32 pid;
+ u32 cpu;
+} entry_key_t;
+
 typedef struct irq_key {
  u32 vec;
  u64 slot;
@@ -64,30 +69,38 @@
  u32 vec;
 } account_val_t;
 
-BPF_HASH(start, u32, account_val_t);
+BPF_HASH(start, entry_key_t, account_val_t);
 BPF_HASH(iptr, u32);
 BPF_HISTOGRAM(dist, irq_key_t);
 
 TRACEPOINT_PROBE(irq, softirq_entry)
 {
- u32 pid = bpf_get_current_pid_tgid();
  account_val_t val = {};
+ entry_key_t key = {};
+
+ key.pid = bpf_get_current_pid_tgid();
+ key.cpu = bpf_get_smp_processor_id();
  val.ts = bpf_ktime_get_ns();
  val.vec = args->vec;
- start.update(&pid, &val);
+
+ start.update(&key, &val);
+
  return 0;
 }
 
 TRACEPOINT_PROBE(irq, softirq_exit)
 {
  u64 delta;
  u32 vec;
- u32 pid = bpf_get_current_pid_tgid();
  account_val_t *valp;
  irq_key_t key = {0};
+ entry_key_t entry_key = {};
+
+ entry_key.pid = bpf_get_current_pid_tgid();
+ entry_key.cpu = bpf_get_smp_processor_id();
 
  // fetch timestamp and calculate delta
- valp = start.lookup(&pid);
+ valp = start.lookup(&entry_key);
  if (valp == 0) {
  return 0; // missed start
  }
@@ -97,7 +110,7 @@
  // store as sum or histogram
  STORE
 
- start.delete(&pid);
+ start.delete(&entry_key);
  return 0;
 }
 """