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
This commit is contained in:
Alexander Motin
2021-06-07 12:02:47 -04:00
committed by Brian Behlendorf
parent b05ae1a82a
commit e76373de7b
5 changed files with 129 additions and 63 deletions
+4
View File
@@ -48,6 +48,8 @@
#define atomic_sub_32_nv(v, i) atomic_sub_return((i), (atomic_t *)(v))
#define atomic_cas_32(v, x, y) atomic_cmpxchg((atomic_t *)(v), x, y)
#define atomic_swap_32(v, x) atomic_xchg((atomic_t *)(v), x)
#define atomic_load_32(v) atomic_read((atomic_t *)(v))
#define atomic_store_32(v, x) atomic_set((atomic_t *)(v), x)
#define atomic_inc_64(v) atomic64_inc((atomic64_t *)(v))
#define atomic_dec_64(v) atomic64_dec((atomic64_t *)(v))
#define atomic_add_64(v, i) atomic64_add((i), (atomic64_t *)(v))
@@ -58,6 +60,8 @@
#define atomic_sub_64_nv(v, i) atomic64_sub_return((i), (atomic64_t *)(v))
#define atomic_cas_64(v, x, y) atomic64_cmpxchg((atomic64_t *)(v), x, y)
#define atomic_swap_64(v, x) atomic64_xchg((atomic64_t *)(v), x)
#define atomic_load_64(v) atomic64_read((atomic64_t *)(v))
#define atomic_store_64(v, x) atomic64_set((atomic64_t *)(v), x)
#ifdef _LP64
static __inline__ void *
+4 -3
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@@ -39,15 +39,16 @@ struct aggsum_bucket {
typedef struct aggsum {
kmutex_t as_lock;
int64_t as_lower_bound;
int64_t as_upper_bound;
uint64_t as_upper_bound;
aggsum_bucket_t *as_buckets ____cacheline_aligned;
uint_t as_numbuckets;
aggsum_bucket_t *as_buckets;
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 *);
int64_t aggsum_upper_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);