A hack to help filter idle time from perf-report

8f88035a · Silas Boyd-Wickizer · 60503d75 · 8f88035a · 8f88035a · 8f88035a
--- a/include/kernel.hh
+++ b/include/kernel.hh
@@ -185,6 +185,7 @@ void            sampstart(void);
 int             sampintr(struct trapframe*);
 void            sampdump(void);
 void            sampconf(void);
+void            sampidle(bool);

 // sched.cc
 void            addrun(struct proc *);

--- a/include/sampler.h
+++ b/include/sampler.h
@@ -9,6 +9,7 @@ struct sampconf {
 #define NTRACE 4

 struct pmuevent {
+  u8 idle:1;
  u64 rip;
  uptr trace[NTRACE];
 };

--- a/kernel/idle.cc
+++ b/kernel/idle.cc
@@ -93,10 +93,12 @@ idleloop(void)
  mtstart(idleloop, myproc());

  sti();
+  sampidle(true);
  for (;;) {
    acquire(&myproc()->lock);
    myproc()->set_state(RUNNABLE);
    sched();
+    sampidle(true);

    finishzombies();


--- a/kernel/sampler.cc
+++ b/kernel/sampler.cc
@@ -26,6 +26,7 @@ struct pmu pmu;
 struct pmulog {
  u64 count;
  u64 capacity;
+  u8 idle:1;                    // Currently idle?
  struct pmuevent *event;
  __padout__;
 } __mpalign__;
@@ -71,6 +72,12 @@ sampdump(void)
 }

 void
+sampidle(bool b)
+{
+  pmulog[myid()].idle = b;
+}
+
+void
 sampconf(void)
 {
  pushcli();
@@ -105,6 +112,7 @@ samplog(struct trapframe *tf)

  e = &l->event[l->count];

+  e->idle = l->idle;
  e->rip = tf->rip;
  getcallerpcs((void*)tf->rbp, e->trace, NELEM(e->trace));
  l->count++;

--- a/kernel/sched.cc
+++ b/kernel/sched.cc
@@ -71,6 +71,8 @@ sched(void)
      release(&myproc()->lock);
      return;
    }
+  } else {
+    sampidle(false);
  }

  if (next->get_state() != RUNNABLE)

--- a/tools/perf-report.cc
+++ b/tools/perf-report.cc
@@ -19,6 +19,7 @@
 #include "include/sampler.h"

 static bool stacktrace_mode = true;
+static bool ignoreidle_mode = false;

 static void __attribute__((noreturn)) 
 edie(const char* errstr, ...) 
@@ -199,8 +200,8 @@ print_entry(Addr2line &addr2line, int count, struct pmuevent *e)
  char *file;
  int line;
  addr2line.lookup(e->rip, &func, &file, &line);
-  printf("%-10u %016"PRIx64" %s:%u %s\n", 
-         count, e->rip, file, line, func);
+  printf("%-8u %4s %016"PRIx64" %s:%u %s\n", 
+         count, e->idle?"idle":"", e->rip, file, line, func);
  free(func);
  free(file);

@@ -211,7 +212,7 @@ print_entry(Addr2line &addr2line, int count, struct pmuevent *e)
    if (e->trace[i] == 0)
      break;
    addr2line.lookup(e->trace[i], &func, &file, &line);    
-    printf("           %016"PRIx64" %s:%u %s\n", 
+    printf("              %016"PRIx64" %s:%u %s\n", 
           e->trace[i], file, line, func);
    free(func);
    free(file);
@@ -264,6 +265,8 @@ main(int ac, char **av)
    p = (struct pmuevent*)(x + header->cpu[i].offset);
    q = (struct pmuevent*)(x + header->cpu[i].offset + header->cpu[i].size);
    for (; p < q; p++) {
+      if (ignoreidle_mode && p->idle)
+        continue;
      auto it = map.find(p);
      if (it == map.end())
        map[p] = 1;