dtracy: make timer probes run in interrupt context

When probing a timer, we were running in our own kproc,
and not in an interrupt context, which meant that we didn't
have any access to anything worth sampling, so we didn't
give any data back.

This moves the probe to the hzclock interrupt, and returns
the pc in the probe.

3 files changed, 15 insertions, 13 deletions

diff --git a/sys/src/9/port/dtracytimer.c b/sys/src/9/port/dtracytimer.c
index 7ca89c1a6..44e63bd52 100644
--- a/sys/src/9/port/dtracytimer.c
+++ b/sys/src/9/port/dtracytimer.c
@@ -4,44 +4,44 @@
 #include	"dat.h"
 #include	"fns.h"
 #include	"../port/error.h"
+#include	"ureg.h"
 
 #include	<dtracy.h>
 
 static DTProbe *timerprobe;
+static int	running;
 
-static void
-dtracytimer(void *)
+void
+dtracytick(Ureg *ur)
 {
 	DTTrigInfo info;
 
+	if(!running)
+		return;
 	memset(&info, 0, sizeof(info));
-	for(;;){
-		tsleep(&up->sleep, return0, nil, 1000);
-		dtptrigger(timerprobe, &info);
-	}
+	info.arg[0] = ur->pc;
+	info.arg[1] = userureg(ur);
+	dtptrigger(timerprobe, &info);
 }
 
 static void
 timerprovide(DTProvider *prov)
 {
-	timerprobe = dtpnew("timer::1s", prov, nil);
+	if(timerprobe == nil)
+		timerprobe = dtpnew("timer::1tk", prov, nil);
 }
 
 static int
 timerenable(DTProbe *)
 {
-	static int gotkproc;
-	
-	if(!gotkproc){
-		kproc("dtracytimer", dtracytimer, nil);
-		gotkproc=1;
-	}
+	running = 1;
 	return 0;
 }
 
 static void
 timerdisable(DTProbe *)
 {
+	running = 0;
 }
 
 DTProvider dtracytimerprov = {
diff --git a/sys/src/9/port/portclock.c b/sys/src/9/port/portclock.c
index 6711815ff..e12938bc3 100644
--- a/sys/src/9/port/portclock.c
+++ b/sys/src/9/port/portclock.c
@@ -154,6 +154,7 @@ hzclock(Ureg *ur)
 	}
 
 	accounttime();
+	dtracytick(ur);
 	kmapinval();
 
 	if(kproftimer != nil)
diff --git a/sys/src/9/port/portfns.h b/sys/src/9/port/portfns.h
index 13666ef30..5fe9fd437 100644
--- a/sys/src/9/port/portfns.h
+++ b/sys/src/9/port/portfns.h
@@ -82,6 +82,7 @@ int		devwstat(Chan*, uchar*, int);
 Dir*		dirchanstat(Chan *);
 void		drawactive(int);
 void		drawcmap(void);
+void		dtracytick(Ureg*);
 void		dumpaproc(Proc*);
 void		dumpregs(Ureg*);
 void		dumpstack(void);