Date: Fri, 11 Mar 2011 00:44:32 +0000 (UTC) From: Jung-uk Kim <jkim@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r219473 - in head/sys: amd64/amd64 contrib/altq/altq i386/i386 pc98/pc98 x86/x86 Message-ID: <201103110044.p2B0iWKM061026@svn.freebsd.org>
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Author: jkim Date: Fri Mar 11 00:44:32 2011 New Revision: 219473 URL: http://svn.freebsd.org/changeset/base/219473 Log: Add a tunable "machdep.disable_tsc" to turn off TSC. Specifically, it turns off boot-time CPU frequency calibration, DELAY(9) with TSC, and using TSC as a CPU ticker. Note tsc_present does not change by this tunable. Modified: head/sys/amd64/amd64/machdep.c head/sys/contrib/altq/altq/altq_subr.c head/sys/i386/i386/machdep.c head/sys/pc98/pc98/machdep.c head/sys/x86/x86/tsc.c Modified: head/sys/amd64/amd64/machdep.c ============================================================================== --- head/sys/amd64/amd64/machdep.c Fri Mar 11 00:38:07 2011 (r219472) +++ head/sys/amd64/amd64/machdep.c Fri Mar 11 00:44:32 2011 (r219473) @@ -80,6 +80,9 @@ __FBSDID("$FreeBSD$"); #include <sys/reboot.h> #include <sys/sched.h> #include <sys/signalvar.h> +#ifdef SMP +#include <sys/smp.h> +#endif #include <sys/syscallsubr.h> #include <sys/sysctl.h> #include <sys/sysent.h> @@ -544,20 +547,22 @@ cpu_est_clockrate(int cpu_id, uint64_t * return (EINVAL); /* If TSC is P-state invariant, DELAY(9) based logic fails. */ - if (tsc_is_invariant) + if (tsc_is_invariant && tsc_freq != 0) return (EOPNOTSUPP); /* If we're booting, trust the rate calibrated moments ago. */ - if (cold) { + if (cold && tsc_freq != 0) { *rate = tsc_freq; return (0); } #ifdef SMP - /* Schedule ourselves on the indicated cpu. */ - thread_lock(curthread); - sched_bind(curthread, cpu_id); - thread_unlock(curthread); + if (smp_cpus > 1) { + /* Schedule ourselves on the indicated cpu. */ + thread_lock(curthread); + sched_bind(curthread, cpu_id); + thread_unlock(curthread); + } #endif /* Calibrate by measuring a short delay. */ @@ -568,12 +573,24 @@ cpu_est_clockrate(int cpu_id, uint64_t * intr_restore(reg); #ifdef SMP - thread_lock(curthread); - sched_unbind(curthread); - thread_unlock(curthread); + if (smp_cpus > 1) { + thread_lock(curthread); + sched_unbind(curthread); + thread_unlock(curthread); + } #endif - *rate = (tsc2 - tsc1) * 1000; + tsc2 -= tsc1; + if (tsc_freq != 0) { + *rate = tsc2 * 1000; + return (0); + } + + /* + * Subtract 0.5% of the total. Empirical testing has shown that + * overhead in DELAY() works out to approximately this value. + */ + *rate = tsc2 * 1000 - tsc2 * 5; return (0); } Modified: head/sys/contrib/altq/altq/altq_subr.c ============================================================================== --- head/sys/contrib/altq/altq/altq_subr.c Fri Mar 11 00:38:07 2011 (r219472) +++ head/sys/contrib/altq/altq/altq_subr.c Fri Mar 11 00:44:32 2011 (r219473) @@ -78,10 +78,10 @@ #include <machine/clock.h> #endif #if defined(__amd64__) || defined(__i386__) +#include <machine/cpu.h> /* for cpu_feature or tsc_present */ #include <machine/cpufunc.h> /* for pentium tsc */ #if defined(__NetBSD__) || defined(__OpenBSD__) #include <machine/specialreg.h> /* for CPUID_TSC */ -#include <machine/cpu.h> /* for cpu_feature */ #endif #endif /* __amd64 || __i386__ */ @@ -927,7 +927,7 @@ init_machclk_setup(void) #if defined(__amd64__) || defined(__i386__) /* check if TSC is available */ #ifdef __FreeBSD__ - if (tsc_freq == 0) + if (!tsc_present || tsc_freq == 0) #else if ((cpu_feature & CPUID_TSC) == 0) #endif Modified: head/sys/i386/i386/machdep.c ============================================================================== --- head/sys/i386/i386/machdep.c Fri Mar 11 00:38:07 2011 (r219472) +++ head/sys/i386/i386/machdep.c Fri Mar 11 00:44:32 2011 (r219473) @@ -79,6 +79,9 @@ __FBSDID("$FreeBSD$"); #include <sys/reboot.h> #include <sys/sched.h> #include <sys/signalvar.h> +#ifdef SMP +#include <sys/smp.h> +#endif #include <sys/syscallsubr.h> #include <sys/sysctl.h> #include <sys/sysent.h> @@ -1142,20 +1145,22 @@ cpu_est_clockrate(int cpu_id, uint64_t * return (EOPNOTSUPP); /* If TSC is P-state invariant, DELAY(9) based logic fails. */ - if (tsc_is_invariant) + if (tsc_is_invariant && tsc_freq != 0) return (EOPNOTSUPP); /* If we're booting, trust the rate calibrated moments ago. */ - if (cold) { + if (cold && tsc_freq != 0) { *rate = tsc_freq; return (0); } #ifdef SMP - /* Schedule ourselves on the indicated cpu. */ - thread_lock(curthread); - sched_bind(curthread, cpu_id); - thread_unlock(curthread); + if (smp_cpus > 1) { + /* Schedule ourselves on the indicated cpu. */ + thread_lock(curthread); + sched_bind(curthread, cpu_id); + thread_unlock(curthread); + } #endif /* Calibrate by measuring a short delay. */ @@ -1166,9 +1171,11 @@ cpu_est_clockrate(int cpu_id, uint64_t * intr_restore(reg); #ifdef SMP - thread_lock(curthread); - sched_unbind(curthread); - thread_unlock(curthread); + if (smp_cpus > 1) { + thread_lock(curthread); + sched_unbind(curthread); + thread_unlock(curthread); + } #endif tsc2 -= tsc1; Modified: head/sys/pc98/pc98/machdep.c ============================================================================== --- head/sys/pc98/pc98/machdep.c Fri Mar 11 00:38:07 2011 (r219472) +++ head/sys/pc98/pc98/machdep.c Fri Mar 11 00:44:32 2011 (r219473) @@ -77,6 +77,9 @@ __FBSDID("$FreeBSD$"); #include <sys/reboot.h> #include <sys/sched.h> #include <sys/signalvar.h> +#ifdef SMP +#include <sys/smp.h> +#endif #include <sys/syscallsubr.h> #include <sys/sysctl.h> #include <sys/sysent.h> @@ -1077,16 +1080,18 @@ cpu_est_clockrate(int cpu_id, uint64_t * return (EOPNOTSUPP); /* If we're booting, trust the rate calibrated moments ago. */ - if (cold) { + if (cold && tsc_freq != 0) { *rate = tsc_freq; return (0); } #ifdef SMP - /* Schedule ourselves on the indicated cpu. */ - thread_lock(curthread); - sched_bind(curthread, cpu_id); - thread_unlock(curthread); + if (smp_cpus > 1) { + /* Schedule ourselves on the indicated cpu. */ + thread_lock(curthread); + sched_bind(curthread, cpu_id); + thread_unlock(curthread); + } #endif /* Calibrate by measuring a short delay. */ @@ -1097,9 +1102,11 @@ cpu_est_clockrate(int cpu_id, uint64_t * intr_restore(reg); #ifdef SMP - thread_lock(curthread); - sched_unbind(curthread); - thread_unlock(curthread); + if (smp_cpus > 1) { + thread_lock(curthread); + sched_unbind(curthread); + thread_unlock(curthread); + } #endif tsc2 -= tsc1; Modified: head/sys/x86/x86/tsc.c ============================================================================== --- head/sys/x86/x86/tsc.c Fri Mar 11 00:38:07 2011 (r219472) +++ head/sys/x86/x86/tsc.c Fri Mar 11 00:44:32 2011 (r219473) @@ -63,6 +63,11 @@ SYSCTL_INT(_kern_timecounter, OID_AUTO, TUNABLE_INT("kern.timecounter.smp_tsc", &smp_tsc); #endif +static int tsc_disabled; +SYSCTL_INT(_machdep, OID_AUTO, disable_tsc, CTLFLAG_RDTUN, &tsc_disabled, 0, + "Disable x86 Time Stamp Counter"); +TUNABLE_INT("machdep.disable_tsc", &tsc_disabled); + static void tsc_freq_changed(void *arg, const struct cf_level *level, int status); static void tsc_freq_changing(void *arg, const struct cf_level *level, @@ -84,12 +89,11 @@ init_TSC(void) { u_int64_t tscval[2]; - if (cpu_feature & CPUID_TSC) - tsc_present = 1; - else - tsc_present = 0; + if ((cpu_feature & CPUID_TSC) == 0) + return; + tsc_present = 1; - if (!tsc_present) + if (tsc_disabled) return; if (bootverbose) @@ -151,7 +155,7 @@ void init_TSC_tc(void) { - if (!tsc_present) + if (!tsc_present || tsc_disabled) return; /* @@ -248,7 +252,7 @@ tsc_freq_changed(void *arg, const struct { /* If there was an error during the transition, don't do anything. */ - if (status != 0) + if (tsc_disabled || status != 0) return; /* Total setting for this level gives the new frequency in MHz. */
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