Files
scylladb/utils/div_ceil.hh
Tomasz Grabiec e2c75d8532 Merge "Fix performance problems with high shard counts tag" from Avi
From http://github.com/avikivity/scylla exponential-sharder/v3.

The sharder, which takes a range of tokens and splits it among shards, is
slow with large shard count and the default
murmur3_partitioner_ignore_msb_bits.

This patchset fixes excessive iteration in sstable sharding metadata writer and
nonsignular range scans.

Without this patchset, sealing a memtable takes > 60 ms on a 48-shard
system.  With the patchset, it drops below the latency tracker threshold I
used (5 ms).

Fixes #2392.

(cherry picked from commit 84648f73ef)
2017-05-17 16:19:24 +03:00

31 lines
938 B
C++

/*
* Copyright (C) 2017 ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
template <typename Dividend, typename Divisor>
inline
// requires Integral<Dividend> && Integral<Divisor>
auto
div_ceil(Dividend dividend, Divisor divisor) {
return (dividend + divisor - 1) / divisor;
}