2 * Copyright (c) 2003-2008 Joseph Koshy
3 * Copyright (c) 2007 The FreeBSD Foundation
6 * Portions of this software were developed by A. Joseph Koshy under
7 * sponsorship from the FreeBSD Foundation and Google, Inc.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
34 #include "opt_hwpmc_hooks.h"
36 #include <sys/types.h>
38 #include <sys/pmckern.h>
40 #include <sys/sysctl.h>
43 FEATURE(hwpmc_hooks, "Kernel support for HW PMC");
44 #define PMC_KERNEL_VERSION PMC_VERSION
46 #define PMC_KERNEL_VERSION 0
49 const int pmc_kernel_version = PMC_KERNEL_VERSION;
52 int (*pmc_hook)(struct thread *td, int function, void *arg) = NULL;
54 /* Interrupt handler */
55 int (*pmc_intr)(int cpu, struct trapframe *tf) = NULL;
57 /* Bitmask of CPUs requiring servicing at hardclock time */
58 volatile cpumask_t pmc_cpumask;
61 * A global count of SS mode PMCs. When non-zero, this means that
62 * we have processes that are sampling the system as a whole.
64 volatile int pmc_ss_count;
67 * Since PMC(4) may not be loaded in the current kernel, the
68 * convention followed is that a non-NULL value of 'pmc_hook' implies
69 * the presence of this kernel module.
71 * This requires us to protect 'pmc_hook' with a
72 * shared (sx) lock -- thus making the process of calling into PMC(4)
73 * somewhat more expensive than a simple 'if' check and indirect call.
80 sx_init_flags(&pmc_sx, "pmc-sx", SX_NOWITNESS);
83 SYSINIT(pmcsx, SI_SUB_LOCK, SI_ORDER_MIDDLE, pmc_init_sx, NULL);
90 * A note on the CPU numbering scheme used by the hwpmc(4) driver.
92 * CPUs are denoted using numbers in the range 0..[pmc_cpu_max()-1].
93 * CPUs could be numbered "sparsely" in this range; the predicate
94 * `pmc_cpu_is_present()' is used to test whether a given CPU is
97 * Further, a CPU that is physically present may be administratively
98 * disabled or otherwise unavailable for use by hwpmc(4). The
99 * `pmc_cpu_is_active()' predicate tests for CPU usability. An
100 * "active" CPU participates in thread scheduling and can field
101 * interrupts raised by PMC hardware.
103 * On systems with hyperthreaded CPUs, multiple logical CPUs may share
104 * PMC hardware resources. For such processors one logical CPU is
105 * denoted as the primary owner of the in-CPU PMC resources. The
106 * pmc_cpu_is_primary() predicate is used to distinguish this primary
107 * CPU from the others.
111 pmc_cpu_is_active(int cpu)
114 return (pmc_cpu_is_present(cpu) &&
115 (hlt_cpus_mask & (1 << cpu)) == 0);
123 pmc_cpu_is_disabled(int cpu)
125 return (!pmc_cpu_is_active(cpu));
129 pmc_cpu_is_present(int cpu)
132 return (!CPU_ABSENT(cpu));
139 pmc_cpu_is_primary(int cpu)
142 return ((logical_cpus_mask & (1 << cpu)) == 0);
150 * Return the maximum CPU number supported by the system. The return
151 * value is used for scaling internal data structures and for runtime
167 * Return the count of CPUs in the `active' state in the system.
170 pmc_cpu_max_active(void)
174 * When support for CPU hot-plugging is added to the kernel,
175 * this function would change to return the current number