diff options
Diffstat (limited to 'sys/kern/kern_pmc.c')
| -rw-r--r-- | sys/kern/kern_pmc.c | 345 |
1 files changed, 345 insertions, 0 deletions
diff --git a/sys/kern/kern_pmc.c b/sys/kern/kern_pmc.c new file mode 100644 index 0000000..2b50be0 --- /dev/null +++ b/sys/kern/kern_pmc.c @@ -0,0 +1,345 @@ +/*- + * Copyright (c) 2003-2008 Joseph Koshy + * Copyright (c) 2007 The FreeBSD Foundation + * All rights reserved. + * + * Portions of this software were developed by A. Joseph Koshy under + * sponsorship from the FreeBSD Foundation and Google, Inc. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "opt_hwpmc_hooks.h" + +#include <sys/types.h> +#include <sys/ctype.h> +#include <sys/param.h> +#include <sys/malloc.h> +#include <sys/kernel.h> +#include <sys/lock.h> +#include <sys/mutex.h> +#include <sys/pmc.h> +#include <sys/pmckern.h> +#include <sys/smp.h> +#include <sys/sysctl.h> +#include <sys/systm.h> + +#ifdef HWPMC_HOOKS +FEATURE(hwpmc_hooks, "Kernel support for HW PMC"); +#define PMC_KERNEL_VERSION PMC_VERSION +#else +#define PMC_KERNEL_VERSION 0 +#endif + +MALLOC_DECLARE(M_PMCHOOKS); +MALLOC_DEFINE(M_PMCHOOKS, "pmchooks", "Memory space for PMC hooks"); + +const int pmc_kernel_version = PMC_KERNEL_VERSION; + +/* Hook variable. */ +int (*pmc_hook)(struct thread *td, int function, void *arg) = NULL; + +/* Interrupt handler */ +int (*pmc_intr)(int cpu, struct trapframe *tf) = NULL; + +/* Bitmask of CPUs requiring servicing at hardclock time */ +volatile cpuset_t pmc_cpumask; + +/* + * A global count of SS mode PMCs. When non-zero, this means that + * we have processes that are sampling the system as a whole. + */ +volatile int pmc_ss_count; + +/* + * Since PMC(4) may not be loaded in the current kernel, the + * convention followed is that a non-NULL value of 'pmc_hook' implies + * the presence of this kernel module. + * + * This requires us to protect 'pmc_hook' with a + * shared (sx) lock -- thus making the process of calling into PMC(4) + * somewhat more expensive than a simple 'if' check and indirect call. + */ +struct sx pmc_sx; + +/* + * PMC Soft per cpu trapframe. + */ +struct trapframe pmc_tf[MAXCPU]; + +/* + * PMC Soft use a global table to store registered events. + */ + +SYSCTL_NODE(_kern, OID_AUTO, hwpmc, CTLFLAG_RW, 0, "HWPMC parameters"); + +static int pmc_softevents = 16; +TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "softevents", &pmc_softevents); +SYSCTL_INT(_kern_hwpmc, OID_AUTO, softevents, CTLFLAG_TUN|CTLFLAG_RD, + &pmc_softevents, 0, "maximum number of soft events"); + +struct mtx pmc_softs_mtx; +int pmc_softs_count; +struct pmc_soft **pmc_softs; + +MTX_SYSINIT(pmc_soft_mtx, &pmc_softs_mtx, "pmc-softs", MTX_SPIN); + +static void +pmc_init_sx(void) +{ + sx_init_flags(&pmc_sx, "pmc-sx", SX_NOWITNESS); +} + +SYSINIT(pmcsx, SI_SUB_LOCK, SI_ORDER_MIDDLE, pmc_init_sx, NULL); + +/* + * Helper functions. + */ + +/* + * A note on the CPU numbering scheme used by the hwpmc(4) driver. + * + * CPUs are denoted using numbers in the range 0..[pmc_cpu_max()-1]. + * CPUs could be numbered "sparsely" in this range; the predicate + * `pmc_cpu_is_present()' is used to test whether a given CPU is + * physically present. + * + * Further, a CPU that is physically present may be administratively + * disabled or otherwise unavailable for use by hwpmc(4). The + * `pmc_cpu_is_active()' predicate tests for CPU usability. An + * "active" CPU participates in thread scheduling and can field + * interrupts raised by PMC hardware. + * + * On systems with hyperthreaded CPUs, multiple logical CPUs may share + * PMC hardware resources. For such processors one logical CPU is + * denoted as the primary owner of the in-CPU PMC resources. The + * pmc_cpu_is_primary() predicate is used to distinguish this primary + * CPU from the others. + */ + +int +pmc_cpu_is_active(int cpu) +{ +#ifdef SMP + return (pmc_cpu_is_present(cpu) && + !CPU_ISSET(cpu, &hlt_cpus_mask)); +#else + return (1); +#endif +} + +/* Deprecated. */ +int +pmc_cpu_is_disabled(int cpu) +{ + return (!pmc_cpu_is_active(cpu)); +} + +int +pmc_cpu_is_present(int cpu) +{ +#ifdef SMP + return (!CPU_ABSENT(cpu)); +#else + return (1); +#endif +} + +int +pmc_cpu_is_primary(int cpu) +{ +#ifdef SMP + return (!CPU_ISSET(cpu, &logical_cpus_mask)); +#else + return (1); +#endif +} + + +/* + * Return the maximum CPU number supported by the system. The return + * value is used for scaling internal data structures and for runtime + * checks. + */ +unsigned int +pmc_cpu_max(void) +{ +#ifdef SMP + return (mp_maxid+1); +#else + return (1); +#endif +} + +#ifdef INVARIANTS + +/* + * Return the count of CPUs in the `active' state in the system. + */ +int +pmc_cpu_max_active(void) +{ +#ifdef SMP + /* + * When support for CPU hot-plugging is added to the kernel, + * this function would change to return the current number + * of "active" CPUs. + */ + return (mp_ncpus); +#else + return (1); +#endif +} + +#endif + +/* + * Cleanup event name: + * - remove duplicate '_' + * - all uppercase + */ +static void +pmc_soft_namecleanup(char *name) +{ + char *p, *q; + + p = q = name; + + for ( ; *p == '_' ; p++) + ; + for ( ; *p ; p++) { + if (*p == '_' && (*(p + 1) == '_' || *(p + 1) == '\0')) + continue; + else + *q++ = toupper(*p); + } + *q = '\0'; +} + +void +pmc_soft_ev_register(struct pmc_soft *ps) +{ + static int warned = 0; + int n; + + ps->ps_running = 0; + ps->ps_ev.pm_ev_code = 0; /* invalid */ + pmc_soft_namecleanup(ps->ps_ev.pm_ev_name); + + mtx_lock_spin(&pmc_softs_mtx); + + if (pmc_softs_count >= pmc_softevents) { + /* + * XXX Reusing events can enter a race condition where + * new allocated event will be used as an old one. + */ + for (n = 0; n < pmc_softevents; n++) + if (pmc_softs[n] == NULL) + break; + if (n == pmc_softevents) { + mtx_unlock_spin(&pmc_softs_mtx); + if (!warned) { + printf("hwpmc: too many soft events, " + "increase kern.hwpmc.softevents tunable\n"); + warned = 1; + } + return; + } + + ps->ps_ev.pm_ev_code = PMC_EV_SOFT_FIRST + n; + pmc_softs[n] = ps; + } else { + ps->ps_ev.pm_ev_code = PMC_EV_SOFT_FIRST + pmc_softs_count; + pmc_softs[pmc_softs_count++] = ps; + } + + mtx_unlock_spin(&pmc_softs_mtx); +} + +void +pmc_soft_ev_deregister(struct pmc_soft *ps) +{ + + KASSERT(ps != NULL, ("pmc_soft_deregister: called with NULL")); + + mtx_lock_spin(&pmc_softs_mtx); + + if (ps->ps_ev.pm_ev_code != 0 && + (ps->ps_ev.pm_ev_code - PMC_EV_SOFT_FIRST) < pmc_softevents) { + KASSERT(ps->ps_ev.pm_ev_code >= PMC_EV_SOFT_FIRST && + ps->ps_ev.pm_ev_code <= PMC_EV_SOFT_LAST, + ("pmc_soft_deregister: invalid event value")); + pmc_softs[ps->ps_ev.pm_ev_code - PMC_EV_SOFT_FIRST] = NULL; + } + + mtx_unlock_spin(&pmc_softs_mtx); +} + +struct pmc_soft * +pmc_soft_ev_acquire(enum pmc_event ev) +{ + struct pmc_soft *ps; + + if (ev == 0 || (ev - PMC_EV_SOFT_FIRST) >= pmc_softevents) + return NULL; + + KASSERT(ev >= PMC_EV_SOFT_FIRST && + ev <= PMC_EV_SOFT_LAST, + ("event out of range")); + + mtx_lock_spin(&pmc_softs_mtx); + + ps = pmc_softs[ev - PMC_EV_SOFT_FIRST]; + if (ps == NULL) + mtx_unlock_spin(&pmc_softs_mtx); + + return ps; +} + +void +pmc_soft_ev_release(struct pmc_soft *ps) +{ + + mtx_unlock_spin(&pmc_softs_mtx); +} + +/* + * Initialise hwpmc. + */ +static void +init_hwpmc(void *dummy __unused) +{ + if (pmc_softevents <= 0 || + pmc_softevents > PMC_EV_DYN_COUNT) { + (void) printf("hwpmc: tunable \"softevents\"=%d out of " + "range.\n", pmc_softevents); + pmc_softevents = PMC_EV_DYN_COUNT; + } + pmc_softs = malloc(pmc_softevents * sizeof(struct pmc_soft *), M_PMCHOOKS, M_NOWAIT|M_ZERO); + KASSERT(pmc_softs != NULL, ("cannot allocate soft events table")); +} + +SYSINIT(hwpmc, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_hwpmc, NULL); + |
