MFP4:

- Implement sampling modes and logging support in hwpmc(4).

- Separate MI and MD parts of hwpmc(4) and allow sharing of
  PMC implementations across different architectures.
  Add support for P4 (EMT64) style PMCs to the amd64 code.

- New pmcstat(8) options: -E (exit time counts) -W (counts
  every context switch), -R (print log file).

- pmc(3) API changes, improve our ability to keep ABI compatibility
  in the future.  Add more 'alias' names for commonly used events.

- bug fixes & documentation.

1 files changed, 6 insertions, 4 deletions

diff --git a/sys/sys/pmckern.h b/sys/sys/pmckern.h
index 7a222da..5f2e158 100644
--- a/sys/sys/pmckern.h
+++ b/sys/sys/pmckern.h
@@ -44,9 +44,6 @@
 #define	PMC_FN_CSW_OUT			3
 #define	PMC_FN_DO_SAMPLES		4
 
-#define	PMC_FN_PROCESS_EXIT		5	/* obsolete */
-#define	PMC_FN_PROCESS_FORK		6	/* obsolete */
-
 /* hook */
 extern int (*pmc_hook)(struct thread *_td, int _function, void *_arg);
 extern int (*pmc_intr)(int _cpu, uintptr_t _pc, int _usermode);
@@ -55,7 +52,10 @@ extern int (*pmc_intr)(int _cpu, uintptr_t _pc, int _usermode);
 extern struct sx pmc_sx;
 
 /* Per-cpu flags indicating availability of sampling data */
-extern cpumask_t pmc_cpumask;
+extern volatile cpumask_t pmc_cpumask;
+
+/* Count of system-wide sampling PMCs in existence */
+extern volatile int pmc_ss_count;
 
 /* Hook invocation; for use within the kernel */
 #define	PMC_CALL_HOOK(t, cmd, arg)		\
@@ -92,6 +92,8 @@ do {						\
 	(__predict_false(atomic_load_acq_int(&(p)->p_flag) &	\
 	    P_HWPMC))
 
+#define	PMC_SYSTEM_SAMPLING_ACTIVE()		(pmc_ss_count > 0)
+
 /* Check if a CPU has recorded samples. */
 #define	PMC_CPU_HAS_SAMPLES(C)	(__predict_false(pmc_cpumask & (1 << (C))))