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@sipa sipa commented Aug 6, 2015

Earlier, when there are only a few entries in the addrman tables, Select() could spin for long periods of time (~200ms), resulting in high CPU usage (up to 40% here). This reduces it to around 0.3ms (0.5% CPU).

@sipa sipa force-pushed the fastselect branch 2 times, most recently from f1abc1b to 9ddf0fd Compare August 6, 2015 18:43
@dgenr8
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dgenr8 commented Aug 7, 2015

utACK

@TheBlueMatt
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utACK

@gmaxwell
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ACK

src/addrman.cpp Outdated
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Equivalent but maybe slightly more readable:

while(vvTried[nKBucket][nKBucketPos] == -1) {
    nKBucket = (nKBucket + insecure_rand()) % ADDRMAN_TRIED_BUCKET_COUNT;
    nKBucketPos = (nKBucketPos + insecure_rand()) % ADDRMAN_BUCKET_SIZE;
}

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Nit addressed.

@dcousens
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utACK

@laanwj laanwj merged commit c33c11e into bitcoin:master Aug 26, 2015
laanwj added a commit that referenced this pull request Aug 26, 2015
c33c11e Improve addrman Select() performance when buckets are nearly empty (Pieter Wuille)
@bitcoin bitcoin locked as resolved and limited conversation to collaborators Sep 8, 2021
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6 participants