mirror_zfs/include/sys/aggsum.h
Alexander Motin e76373de7b More aggsum optimizations
- Avoid atomic_add() when updating as_lower_bound/as_upper_bound.
Previous code was excessively strong on 64bit systems while not
strong enough on 32bit ones.  Instead introduce and use real
atomic_load() and atomic_store() operations, just an assignments
on 64bit machines, but using proper atomics on 32bit ones to avoid
torn reads/writes.

 - Reduce number of buckets on large systems.  Extra buckets not as
much improve add speed, as hurt reads.  Unlike wmsum for aggsum
reads are still important.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes #12145
2021-06-09 13:05:34 -07:00

61 lines
1.3 KiB
C

/*
* CDDL HEADER START
*
* 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.
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2017 by Delphix. All rights reserved.
*/
#ifndef _SYS_AGGSUM_H
#define _SYS_AGGSUM_H
#include <sys/zfs_context.h>
#ifdef __cplusplus
extern "C" {
#endif
typedef struct aggsum_bucket aggsum_bucket_t;
struct aggsum_bucket {
kmutex_t asc_lock;
int64_t asc_delta;
uint64_t asc_borrowed;
} ____cacheline_aligned;
/*
* Fan out over FANOUT cpus.
*/
typedef struct aggsum {
kmutex_t as_lock;
int64_t as_lower_bound;
uint64_t as_upper_bound;
aggsum_bucket_t *as_buckets ____cacheline_aligned;
uint_t as_numbuckets;
uint_t as_bucketshift;
} aggsum_t;
void aggsum_init(aggsum_t *, uint64_t);
void aggsum_fini(aggsum_t *);
int64_t aggsum_lower_bound(aggsum_t *);
uint64_t aggsum_upper_bound(aggsum_t *);
int aggsum_compare(aggsum_t *, uint64_t);
uint64_t aggsum_value(aggsum_t *);
void aggsum_add(aggsum_t *, int64_t);
#ifdef __cplusplus
}
#endif
#endif /* _SYS_AGGSUM_H */