Three Times Fifteen Minutes Runs on perro with 5.2-wl86 key cache partitions off, 8, and 32 and key buffer size 400

From Askmonty.org

MariDB sysbench benchmark comparison for key_cache_partitions in % with key_buffer_size = 400MB

Each test was run 3 times for 15 minutes with 3 minutes warmup.

                  Number of threads
                    1       4       8       16      32      64      128
sysbench test
 oltp_complex_ro
     8 / off        -0.78   -0.42   -0.18   -0.49   -1.03   -0.64    1.08
    32 / off        -0.38   -0.30    0.55   -0.39   -0.75   -0.05    2.49
 oltp_simple
     8 / off        -1.19   -2.20   -0.74   -2.74   -1.54    0.28   -1.46
    32 / off        -1.24   -1.22    0.33   -0.13    0.11    2.09   -1.34
 select
     8 / off        -0.71   -1.68   -1.48   -2.05    0.94   -2.93   -0.18
    32 / off        -0.71   -1.33   -2.11   -0.63   -0.40  -19.68* -11.45*
 update_index
     8 / off        -1.30    4.37  -14.69*  -2.56   17.69*  -1.14    2.82
    32 / off        -1.47    7.03*   0.71   -0.72   15.61*   1.61    0.33

( 8/off*100)-100
(32/off*100)-100

* means due to unusual high STDEV (see OO.org spreadsheet for details)

off means key_cache_partitions off
  8 means key_cache_partitions = 8
 32 means key_cache_partitions = 32
 

Benchmark was ran on perro: Quad core Intel 3.2GHz. with 2GB RAM

MariaDB and MySQL was compiled with

 BUILD/compile-amd64-max
 

MariaDB revision is: revno: 2742 committer: Igor Babaev <igor@askmonty.org> branch nick: maria-5.2-keycache timestamp: Tue 2010-02-16 08:41:11 -0800 message:

 WL#86: Partitioned key cache for MyISAM.
 This is the base patch for the task.

sysbench was run with this parameters:

 --oltp-table-size=20000000 \       # 20 million rows.
 --max-requests=0 \
 --mysql-table-engine=MyISAM \
 --mysql-user=root \
 --mysql-engine-trx=no \
 --myisam-max-rows=50000000 \
 --rand-seed=303
 

and this variable part of parameters

 --num-threads=$THREADS --test=${TEST_DIR}/${SYSBENCH_TEST}

Configuration used for MariDB:

 --no-defaults \
 --datadir=/mnt/data/sysbench/data \
 --language=./sql/share/english \
 --key_buffer_size=400M \
 --key_cache_partitions=32 \        # Off | 8 | 32
 --max_connections=256 \
 --query_cache_size=0 \
 --query_cache_type=0 \
 --skip-grant-tables \
 --socket=/tmp/mysql.sock \
 --table_open_cache=512 \
 --thread_cache=512 \
 --tmpdir=/mnt/data/sysbench