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/*
* This file and its contents are supplied under the terms of the
* Common Development and Distribution License ("CDDL"), version 1.0.
* You may only use this file in accordance with the terms of version
* 1.0 of the CDDL.
*
* A full copy of the text of the CDDL should have accompanied this
* source. A copy of the CDDL is also available via the Internet at
* http://www.illumos.org/license/CDDL.
*/
/*
* Copyright (c) 2018, Joyent, Inc.
*/
/*
* Use a cpu_uarray_t for an array of uint64_t values that are written on a
* per-CPU basis. We align each CPU on a 128-byte boundary (so two cachelines).
* It's not clear why, but this can have a significant effect in multi-socket
* systems running certain benchmarks on a relatively current Intel system.
*
* So the layout is like this, for example:
*
* 0: STAT1 for CPU 0
* 8: STAT2 for CPU 0
* 16: STAT3 for CPU 0
* 24: padding
* 128: STAT1 for CPU 1
* 136: STAT2 for CPU 1
* ...
*
* At collection time, cpu_uarray_sum() can be used to sum the given value index
* across all CPUs, or cpu_uarray_sum_all() sums all stats across all CPUs.
* The summation is done such that it saturates at UINT64_MAX.
*/
#ifndef _SYS_CPU_UARRAY_H
#define _SYS_CPU_UARRAY_H
#include <sys/types.h>
#ifdef __cplusplus
extern "C" {
#endif
#ifdef _KERNEL
/*
* Trying to include sysmacros.h for P2ROUNDUP() here is just too painful.
*/
#define CUA_ROUNDUP(x, align) (-(-(x) & -(align)))
#define CUA_ALIGN (128)
#define CUA_CPU_STRIDE(nr_items) \
CUA_ROUNDUP((nr_items), CUA_ALIGN / sizeof (uint64_t))
#define CUA_INDEX(nr_items, c, i) (((c) * CUA_CPU_STRIDE(nr_items)) + (i))
#define CPU_UARRAY_VAL(cua, cpu_index, stat_index) \
((cua)->cu_vals[CUA_INDEX((cua)->cu_nr_items, cpu_index, stat_index)])
typedef struct {
uint64_t cu_nr_items;
char cu_pad[CUA_ALIGN - sizeof (uint64_t)];
#ifdef __lint
volatile uint64_t cu_vals[1];
#else
volatile uint64_t cu_vals[];
#endif
} cpu_uarray_t __aligned(CUA_ALIGN);
extern cpu_uarray_t *cpu_uarray_zalloc(size_t, int);
extern void cpu_uarray_free(cpu_uarray_t *);
extern uint64_t cpu_uarray_sum(cpu_uarray_t *, size_t);
extern uint64_t cpu_uarray_sum_all(cpu_uarray_t *);
#endif /* _KERNEL */
#ifdef __cplusplus
}
#endif
#endif /* _SYS_CPU_UARRAY_H */
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