Date: Fri, 16 Mar 2007 23:54:02 -0700 From: Nate Lawson <nate@root.org> To: arch@freebsd.org Subject: PATCH: cpu freq notifiers and eventhandler register from SYSINIT Message-ID: <45FB908A.6070006@root.org>
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Attached is an updated patch for handling cpu freq changes. It updates
tsc_freq and all direct consumers of it.
I also would like to add something to eventhandler.h. As I was doing
this, I really wanted a way to declare an eventhandler tag and call
eventhandler_register() from a SYSINIT. I ended up doing that manually
in a lot of cases where I couldn't register up front because it was too
early in boot (i.e. identcpu). Comments on adding this macro, similar
to TASQUEUE_DEFINE in taskqueue.h? Maybe EVENTHANDLER_REGISTER_INIT()?
I wasn't sure what to do for guprof since it is using TSC at times. I
decided to just have it print a warning if the TSC freq changed while
profiling was active. Let me know if I should do something else here.
For altq, it should be correct but please check my change. I'm not sure
what to do for packets that are being processed if machclk_freq changes.
It might be ok.
Thanks,
--
Nate
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filename="cpu_event.diff"
Index: sys/i386/i386/tsc.c
===================================================================
RCS file: /home/ncvs/src/sys/i386/i386/tsc.c,v
retrieving revision 1.206
diff -u -r1.206 tsc.c
--- sys/i386/i386/tsc.c 4 Aug 2006 07:56:35 -0000 1.206
+++ sys/i386/i386/tsc.c 17 Mar 2007 01:25:14 -0000
@@ -30,6 +30,8 @@
#include "opt_clock.h"
#include <sys/param.h>
+#include <sys/bus.h>
+#include <sys/cpu.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/time.h>
@@ -52,14 +54,20 @@
TUNABLE_INT("kern.timecounter.smp_tsc", &smp_tsc);
#endif
+static eventhandler_tag evh_pre_tag, evh_post_tag;
+
static unsigned tsc_get_timecount(struct timecounter *tc);
+static void tsc_freq_changing(void *arg, const struct cf_level *level,
+ int *status);
+static void tsc_freq_changed(void *arg, const struct cf_level *level,
+ int status);
static struct timecounter tsc_timecounter = {
tsc_get_timecount, /* get_timecount */
0, /* no poll_pps */
- ~0u, /* counter_mask */
+ ~0u, /* counter_mask */
0, /* frequency */
- "TSC", /* name */
+ "TSC", /* name */
800, /* quality (adjusted in code) */
};
@@ -87,8 +95,13 @@
if (bootverbose)
printf("TSC clock: %ju Hz\n", (intmax_t)tsc_freq);
set_cputicker(rdtsc, tsc_freq, 1);
-}
+ /* Register to find out about changes in CPU frequency. */
+ evh_pre_tag = EVENTHANDLER_REGISTER(cpufreq_pre_change,
+ tsc_freq_changing, NULL, EVENTHANDLER_PRI_FIRST);
+ evh_post_tag = EVENTHANDLER_REGISTER(cpufreq_post_change,
+ tsc_freq_changed, NULL, EVENTHANDLER_PRI_FIRST);
+}
void
init_TSC_tc(void)
@@ -128,6 +141,38 @@
}
}
+/*
+ * If the TSC timecounter is in use, veto the pending change. It may be
+ * possible in the future to handle a dynamically-changing timecounter rate.
+ */
+static void
+tsc_freq_changing(void *arg, const struct cf_level *level, int *status)
+{
+ static int once;
+
+ if (*status == 0 && timecounter == &tsc_timecounter) {
+ if (!once) {
+ printf("timecounter TSC must not be in use when "
+ "changing frequencies; change denied\n");
+ once = 1;
+ }
+ *status = EBUSY;
+ }
+}
+
+/* Update TSC freq with the value indicated by the caller. */
+static void
+tsc_freq_changed(void *arg, const struct cf_level *level, int status)
+{
+ /* If there was an error during the transition, don't do anything. */
+ if (status != 0)
+ return;
+
+ /* Total setting for this level gives the new frequency in MHz. */
+ tsc_freq = level->total_set.freq * 1000000;
+ tsc_timecounter.tc_frequency = tsc_freq;
+}
+
static int
sysctl_machdep_tsc_freq(SYSCTL_HANDLER_ARGS)
{
Index: sys/i386/i386/identcpu.c
===================================================================
RCS file: /home/ncvs/src/sys/i386/i386/identcpu.c,v
retrieving revision 1.172
diff -u -r1.172 identcpu.c
--- sys/i386/i386/identcpu.c 12 Mar 2007 20:27:21 -0000 1.172
+++ sys/i386/i386/identcpu.c 17 Mar 2007 06:30:34 -0000
@@ -45,6 +45,8 @@
#include <sys/param.h>
#include <sys/bus.h>
+#include <sys/cpu.h>
+#include <sys/eventhandler.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
@@ -101,6 +103,9 @@
&hw_clockrate, 0, "CPU instruction clock rate");
static char cpu_brand[48];
+static eventhandler_tag evh_post_tag;
+static void tsc_freq_changed(void *arg, const struct cf_level *level,
+ int status);
#define MAX_BRAND_INDEX 8
@@ -1077,6 +1082,29 @@
write_eflags(eflags);
}
+/* XXX Register with sysinit should be a macro in eventhandler.h */
+static void
+ident_tsc_check(void *arg)
+{
+
+ evh_post_tag = EVENTHANDLER_REGISTER(cpufreq_post_change,
+ tsc_freq_changed, NULL, EVENTHANDLER_PRI_ANY);
+}
+SYSINIT(ident_tsc_check, SI_SUB_CONFIGURE, SI_ORDER_ANY, ident_tsc_check,
+ NULL);
+
+/* Update TSC freq with the value indicated by the caller. */
+static void
+tsc_freq_changed(void *arg, const struct cf_level *level, int status)
+{
+ /* If there was an error during the transition, don't do anything. */
+ if (status != 0)
+ return;
+
+ /* Total setting for this level gives the new frequency in MHz. */
+ hw_clockrate = level->total_set.freq;
+}
+
/*
* Final stage of CPU identification. -- Should I check TI?
*/
Index: sys/kern/kern_cpu.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_cpu.c,v
retrieving revision 1.23
diff -u -r1.23 kern_cpu.c
--- sys/kern/kern_cpu.c 3 Mar 2006 02:06:04 -0000 1.23
+++ sys/kern/kern_cpu.c 17 Mar 2007 01:23:40 -0000
@@ -1,5 +1,5 @@
/*-
- * Copyright (c) 2004-2005 Nate Lawson (SDG)
+ * Copyright (c) 2004-2007 Nate Lawson (SDG)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -95,7 +95,6 @@
static int cpufreq_attach(device_t dev);
static int cpufreq_detach(device_t dev);
-static void cpufreq_evaluate(void *arg);
static int cf_set_method(device_t dev, const struct cf_level *level,
int priority);
static int cf_get_method(device_t dev, struct cf_level *level);
@@ -127,8 +126,6 @@
static devclass_t cpufreq_dc;
DRIVER_MODULE(cpufreq, cpu, cpufreq_driver, cpufreq_dc, 0, 0);
-static eventhandler_tag cf_ev_tag;
-
static int cf_lowest_freq;
static int cf_verbose;
TUNABLE_INT("debug.cpufreq.lowest", &cf_lowest_freq);
@@ -176,8 +173,6 @@
SYSCTL_CHILDREN(device_get_sysctl_tree(parent)),
OID_AUTO, "freq_levels", CTLTYPE_STRING | CTLFLAG_RD, sc, 0,
cpufreq_levels_sysctl, "A", "CPU frequency levels");
- cf_ev_tag = EVENTHANDLER_REGISTER(cpufreq_changed, cpufreq_evaluate,
- NULL, EVENTHANDLER_PRI_ANY);
return (0);
}
@@ -202,18 +197,11 @@
numdevs = devclass_get_count(cpufreq_dc);
if (numdevs == 1) {
CF_DEBUG("final shutdown for %s\n", device_get_nameunit(dev));
- EVENTHANDLER_DEREGISTER(cpufreq_changed, cf_ev_tag);
}
return (0);
}
-static void
-cpufreq_evaluate(void *arg)
-{
- /* TODO: Re-evaluate when notified of changes to drivers. */
-}
-
static int
cf_set_method(device_t dev, const struct cf_level *level, int priority)
{
@@ -222,26 +210,16 @@
struct cf_saved_freq *saved_freq, *curr_freq;
struct pcpu *pc;
int cpu_id, error, i;
- static int once;
sc = device_get_softc(dev);
error = 0;
set = NULL;
saved_freq = NULL;
- /*
- * Check that the TSC isn't being used as a timecounter.
- * If it is, then return EBUSY and refuse to change the
- * clock speed.
- */
- if (strcmp(timecounter->tc_name, "TSC") == 0) {
- if (!once) {
- printf("cpufreq: frequency change with timecounter"
- " TSC not allowed, see cpufreq(4)\n");
- once = 1;
- }
- return (EBUSY);
- }
+ /* We are going to change levels so notify the pre-change handler. */
+ EVENTHANDLER_INVOKE(cpufreq_pre_change, level, &error);
+ if (error != 0)
+ return (error);
CF_MTX_LOCK(&sc->lock);
@@ -378,8 +356,15 @@
out:
CF_MTX_UNLOCK(&sc->lock);
+
+ /*
+ * We changed levels (or attempted to) so notify the post-change
+ * handler of new frequency or error.
+ */
+ EVENTHANDLER_INVOKE(cpufreq_post_change, level, error);
if (error && set)
device_printf(set->dev, "set freq failed, err %d\n", error);
+
return (error);
}
Index: sys/sys/cpu.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/cpu.h,v
retrieving revision 1.3
diff -u -r1.3 cpu.h
--- sys/sys/cpu.h 19 Feb 2005 06:13:25 -0000 1.3
+++ sys/sys/cpu.h 17 Mar 2007 01:44:18 -0000
@@ -1,5 +1,5 @@
/*-
- * Copyright (c) 2005 Nate Lawson (SDG)
+ * Copyright (c) 2005-2007 Nate Lawson (SDG)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -29,6 +29,8 @@
#ifndef _SYS_CPU_H_
#define _SYS_CPU_H_
+#include <sys/eventhandler.h>
+
/*
* CPU device support.
*/
@@ -118,6 +120,12 @@
int cpufreq_register(device_t dev);
int cpufreq_unregister(device_t dev);
+/* Eventhandlers that are called before and after a change in frequency */
+typedef void (*cpufreq_pre_notify_fn)(void *, const struct cf_level *, int *);
+typedef void (*cpufreq_post_notify_fn)(void *, const struct cf_level *, int);
+EVENTHANDLER_DECLARE(cpufreq_pre_change, cpufreq_pre_notify_fn);
+EVENTHANDLER_DECLARE(cpufreq_post_change, cpufreq_post_notify_fn);
+
/* Allow values to be +/- a bit since sometimes we have to estimate. */
#define CPUFREQ_CMP(x, y) (abs((x) - (y)) < 25)
Index: sys/contrib/altq/altq/altq_subr.c
===================================================================
RCS file: /home/ncvs/src/sys/contrib/altq/altq/altq_subr.c,v
retrieving revision 1.8
diff -u -r1.8 altq_subr.c
--- sys/contrib/altq/altq/altq_subr.c 2 Mar 2006 00:51:39 -0000 1.8
+++ sys/contrib/altq/altq/altq_subr.c 17 Mar 2007 02:10:01 -0000
@@ -74,6 +74,9 @@
#if __FreeBSD__ < 3
#include "opt_cpu.h" /* for FreeBSD-2.2.8 to get i586_ctr_freq */
#endif
+#include <sys/bus.h>
+#include <sys/cpu.h>
+#include <sys/eventhandler.h>
#include <machine/clock.h>
#endif
#if defined(__i386__)
@@ -898,6 +901,22 @@
extern u_int64_t cpu_tsc_freq;
#endif /* __alpha__ */
+#if defined(__FreeBSD__) && (__FreeBSD_version > 700030)
+static eventhandler_tag evh_post_tag;
+
+/* Update TSC freq with the value indicated by the caller. */
+static void
+tsc_freq_changed(void *arg, const struct cf_level *level, int status)
+{
+ /* If there was an error during the transition, don't do anything. */
+ if (status != 0)
+ return;
+
+ /* Total setting for this level gives the new frequency in MHz. */
+ machclk_freq = level->total_set.freq * 1000000;
+}
+#endif /* __FreeBSD_version > 700030 */
+
void
init_machclk(void)
{
@@ -941,6 +960,11 @@
#ifdef __FreeBSD__
#if (__FreeBSD_version > 300000)
machclk_freq = tsc_freq;
+#if (__FreeBSD_version > 700030)
+ /* Register to see any changes in TSC freq. */
+ evh_post_tag = EVENTHANDLER_REGISTER(cpufreq_post_change,
+ tsc_freq_changed, NULL, EVENTHANDLER_PRI_ANY);
+#endif
#else
machclk_freq = i586_ctr_freq;
#endif
Index: sys/i386/isa/prof_machdep.c
===================================================================
RCS file: /home/ncvs/src/sys/i386/isa/prof_machdep.c,v
retrieving revision 1.29
diff -u -r1.29 prof_machdep.c
--- sys/i386/isa/prof_machdep.c 29 Oct 2006 09:48:44 -0000 1.29
+++ sys/i386/isa/prof_machdep.c 17 Mar 2007 06:06:17 -0000
@@ -33,6 +33,9 @@
#include <sys/param.h>
#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/cpu.h>
+#include <sys/eventhandler.h>
#include <sys/gmon.h>
#include <sys/kernel.h>
#include <sys/smp.h>
@@ -50,6 +53,7 @@
int cputime_bias = 1; /* initialize for locality of reference */
+static int prof_active;
static int cputime_clock = CPUTIME_CLOCK_UNINITIALIZED;
#if defined(PERFMON) && defined(I586_PMC_GUPROF)
static u_int cputime_clock_pmc_conf = I586_PMC_GUPROF;
@@ -58,6 +62,10 @@
#endif
#endif /* GUPROF */
+static eventhandler_tag evh_post_tag;
+static void tsc_freq_changed(void *arg, const struct cf_level *level,
+ int status);
+
#ifdef __GNUCLIKE_ASM
__asm(" \n\
GM_STATE = 0 \n\
@@ -287,7 +295,7 @@
if (cputime_clock == CPUTIME_CLOCK_UNINITIALIZED) {
cputime_clock = CPUTIME_CLOCK_I8254;
#if defined(I586_CPU) || defined(I686_CPU)
- if (tsc_freq != 0 && !tsc_is_broken && mp_ncpus < 2)
+ if (tsc_freq != 0 && !tsc_is_broken && mp_ncpus == 1)
cputime_clock = CPUTIME_CLOCK_TSC;
#endif
}
@@ -322,6 +330,7 @@
}
#endif /* PERFMON && I586_PMC_GUPROF */
#endif /* I586_CPU || I686_CPU */
+ prof_active = 1;
cputime_bias = 0;
cputime();
}
@@ -337,5 +346,32 @@
cputime_clock_pmc_init = FALSE;
}
#endif
+ prof_active = 0;
+}
+
+/* XXX Register with sysinit should be a macro in eventhandler.h */
+static void
+guprof_tsc_check(void *arg)
+{
+
+ evh_post_tag = EVENTHANDLER_REGISTER(cpufreq_post_change,
+ tsc_freq_changed, NULL, EVENTHANDLER_PRI_ANY);
+}
+SYSINIT(guprof_tsc_check, SI_SUB_CONFIGURE, SI_ORDER_ANY, guprof_tsc_check,
+ NULL);
+
+/* If the cpu frequency changed while profiling, report a warning. */
+static void
+tsc_freq_changed(void *arg, const struct cf_level *level, int status)
+{
+ static int once;
+
+ /* If there was an error during the transition, don't do anything. */
+ if (status != 0)
+ return;
+ if (prof_active && cputime_clock == CPUTIME_CLOCK_TSC && !once) {
+ printf("warning: cpu freq changed while profiling active\n");
+ once = 1;
+ }
}
#endif /* GUPROF */
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