svn commit: r237859 - in projects/calloutng/sys: conf kern

[Davide Italiano]

Author: davide
Date: Sat Jun 30 23:34:33 2012
New Revision: 237859
URL: http://svn.freebsd.org/changeset/base/237859

Log:
  Add a new CALLOUT_PROFILING option so that SYSCTLs on the wheel may be
  selectively disabled/enabled. Reintroduce a SYSCTL that I wrongly removed
  in a previous commit. Selectively disabling this sort of rudimentary
  profiling may have a good effect on CPU caches because same variable is not
  accessed anymore by different CPUs.
  
  Discussed with:		mav

Modified:
  projects/calloutng/sys/conf/NOTES
  projects/calloutng/sys/conf/options
  projects/calloutng/sys/kern/kern_timeout.c

Modified: projects/calloutng/sys/conf/NOTES
==============================================================================
--- projects/calloutng/sys/conf/NOTES	Sat Jun 30 23:29:34 2012	(r237858)
+++ projects/calloutng/sys/conf/NOTES	Sat Jun 30 23:34:33 2012	(r237859)
@@ -1,4 +1,4 @@
-# $FreeBSD$
+
 #
 # NOTES -- Lines that can be cut/pasted into kernel and hints configs.
 #
@@ -259,6 +259,8 @@ options 	SX_NOINLINE
 
 # SMP Debugging Options:
 #
+# CALLOUT_PROFILING enables rudimentary profiling of the callwheel data
+#	  structure used as backend in callout(9).
 # PREEMPTION allows the threads that are in the kernel to be preempted by
 #	  higher priority [interrupt] threads.  It helps with interactivity
 #	  and allows interrupt threads to run sooner rather than waiting.
@@ -297,6 +299,9 @@ options 	LOCK_PROFILING
 options 	MPROF_BUFFERS="1536"
 options 	MPROF_HASH_SIZE="1543"
 
+# Profiling for the callout(9) backend.
+options 	CALLOUT_PROFILING
+
 # Profiling for internal hash tables.
 options 	SLEEPQUEUE_PROFILING
 options 	TURNSTILE_PROFILING

Modified: projects/calloutng/sys/conf/options
==============================================================================
--- projects/calloutng/sys/conf/options	Sat Jun 30 23:29:34 2012	(r237858)
+++ projects/calloutng/sys/conf/options	Sat Jun 30 23:34:33 2012	(r237859)
@@ -66,6 +66,7 @@ SYSCTL_DEBUG	opt_sysctl.h
 ADAPTIVE_LOCKMGRS
 ALQ
 AUDIT		opt_global.h
+CALLOUT_PROFILING
 CAPABILITIES	opt_capsicum.h
 CAPABILITY_MODE	opt_capsicum.h
 CODA_COMPAT_5	opt_coda.h

Modified: projects/calloutng/sys/kern/kern_timeout.c
==============================================================================
--- projects/calloutng/sys/kern/kern_timeout.c	Sat Jun 30 23:29:34 2012	(r237858)
+++ projects/calloutng/sys/kern/kern_timeout.c	Sat Jun 30 23:34:33 2012	(r237859)
@@ -37,6 +37,7 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include "opt_callout_profiling.h"
 #include "opt_kdtrace.h"
 
 #include <sys/param.h>
@@ -69,6 +70,10 @@ SDT_PROBE_DEFINE(callout_execute, kernel
 SDT_PROBE_ARGTYPE(callout_execute, kernel, , callout_end, 0,
     "struct callout *");
 
+#ifdef CALLOUT_PROFILING	
+static int avg_depth;
+SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0,
+    "Average number of items examined per softclock call. Units = 1/1000");
 static int avg_gcalls;
 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0,
     "Average number of Giant callouts made per softclock call. Units = 1/1000");
@@ -78,6 +83,7 @@ SYSCTL_INT(_debug, OID_AUTO, to_avg_lock
 static int avg_mpcalls;
 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0,
     "Average number of MP callouts made per softclock call. Units = 1/1000");
+#endif
 /*
  * TODO:
  *	allocate more timeout table slots when table overflows.
@@ -784,10 +790,12 @@ softclock(void *arg)
 			steps = 0;
 		}	
 	}
-
+#ifdef CALLOUT_PROFILING
+	avg_depth += (depth * 1000 - avg_depth) >> 8;
 	avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8;
 	avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8;
 	avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8;
+#endif
 	cc->cc_next = NULL;
 	CC_UNLOCK(cc);
 }