chore: prefetch keys in opmget #4778
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Also, stop deduplicating keys by default, but keep it as a run-time flag. All in all, this PR improves MGET (100% miss) throughput by at least 7%: from 1.23M to 1.32M qps. (100% miss traffic allows measuring more effectively the impact of this code) Also, finally fix TieredStorageTest.FlushAll test. Signed-off-by: Roman Gershman <roman@dragonflydb.io>
BorysTheDev
approved these changes
Mar 17, 2025
BorysTheDev
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Mar 17, 2025
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| constexpr unsigned kPrefetchLimit = 32; | ||
| if (mget_prefetch_keys) { | ||
| unsigned prefetched = 0; | ||
| for (string_view key : keys) { | ||
| pt.Prefetch(key); | ||
| if (++prefetched >= kPrefetchLimit) { | ||
| break; | ||
| } | ||
| } | ||
| } |
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Can we move it before key_index.reserve() or even higher to have more time for memory prefetching?
dranikpg
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Apr 8, 2025
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Also, stop deduplicating keys by default, but keep it as a run-time flag.
All in all, this PR improves MGET (100% miss) throughput by at least 7%:
from 1.23M to 1.32M qps.
(100% miss traffic allows measuring more effectively the impact of this code)
Also, finally fix TieredStorageTest.FlushAll test.