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| author | Marko Mäkelä <marko.makela@mariadb.com> | 2019-12-10 11:23:46 +0200 |
|---|---|---|
| committer | Marko Mäkelä <marko.makela@mariadb.com> | 2019-12-10 17:01:36 +0200 |
| commit | 41e6a154ece1c7d49becac0ccaa72f507686d298 (patch) | |
| tree | f4329da603e99b1f9576dd6eeec54ccf1a0d07e0 /mysql-test | |
| parent | b1f2d3a8c8d9bd10e088111ca966b3f7be35df35 (diff) | |
| download | mariadb-git-41e6a154ece1c7d49becac0ccaa72f507686d298.tar.gz | |
MDEV-14482 - Cache line contention on ut_rnd_interval()
InnoDB RNG maintains global state, causing otherwise unnecessary bus
traffic. Even worse, this is cross-mutex traffic. That is, different
mutexes suffer from contention.
Fixed delay of 4 was verified to give best throughput by OLTP update
index and read-write benchmarks on Intel Broadwell (2/20/40) and
ARM (1/46/46).
This is a backport of ce0479006523bc72ed6abb703bd1f87ff256fd8a from
MariaDB Server 10.3.
Diffstat (limited to 'mysql-test')
| -rw-r--r-- | mysql-test/suite/sys_vars/r/innodb_spin_wait_delay_basic.result | 16 | ||||
| -rw-r--r-- | mysql-test/suite/sys_vars/r/sysvars_innodb.result | 4 |
2 files changed, 10 insertions, 10 deletions
diff --git a/mysql-test/suite/sys_vars/r/innodb_spin_wait_delay_basic.result b/mysql-test/suite/sys_vars/r/innodb_spin_wait_delay_basic.result index 88516a854fe..b76ba4933f2 100644 --- a/mysql-test/suite/sys_vars/r/innodb_spin_wait_delay_basic.result +++ b/mysql-test/suite/sys_vars/r/innodb_spin_wait_delay_basic.result @@ -1,28 +1,28 @@ SET @start_global_value = @@global.innodb_spin_wait_delay; SELECT @start_global_value; @start_global_value -6 +4 Valid values are zero or above select @@global.innodb_spin_wait_delay >=0; @@global.innodb_spin_wait_delay >=0 1 select @@global.innodb_spin_wait_delay; @@global.innodb_spin_wait_delay -6 +4 select @@session.innodb_spin_wait_delay; ERROR HY000: Variable 'innodb_spin_wait_delay' is a GLOBAL variable show global variables like 'innodb_spin_wait_delay'; Variable_name Value -innodb_spin_wait_delay 6 +innodb_spin_wait_delay 4 show session variables like 'innodb_spin_wait_delay'; Variable_name Value -innodb_spin_wait_delay 6 +innodb_spin_wait_delay 4 select * from information_schema.global_variables where variable_name='innodb_spin_wait_delay'; VARIABLE_NAME VARIABLE_VALUE -INNODB_SPIN_WAIT_DELAY 6 +INNODB_SPIN_WAIT_DELAY 4 select * from information_schema.session_variables where variable_name='innodb_spin_wait_delay'; VARIABLE_NAME VARIABLE_VALUE -INNODB_SPIN_WAIT_DELAY 6 +INNODB_SPIN_WAIT_DELAY 4 set global innodb_spin_wait_delay=10; select @@global.innodb_spin_wait_delay; @@global.innodb_spin_wait_delay @@ -38,7 +38,7 @@ ERROR HY000: Variable 'innodb_spin_wait_delay' is a GLOBAL variable and should b set global innodb_spin_wait_delay=DEFAULT; select @@global.innodb_spin_wait_delay; @@global.innodb_spin_wait_delay -6 +4 set global innodb_spin_wait_delay=0; select @@global.innodb_spin_wait_delay; @@global.innodb_spin_wait_delay @@ -111,4 +111,4 @@ INNODB_SPIN_WAIT_DELAY 0 SET @@global.innodb_spin_wait_delay = @start_global_value; SELECT @@global.innodb_spin_wait_delay; @@global.innodb_spin_wait_delay -6 +4 diff --git a/mysql-test/suite/sys_vars/r/sysvars_innodb.result b/mysql-test/suite/sys_vars/r/sysvars_innodb.result index 65d47347a15..4be85752cc7 100644 --- a/mysql-test/suite/sys_vars/r/sysvars_innodb.result +++ b/mysql-test/suite/sys_vars/r/sysvars_innodb.result @@ -2228,10 +2228,10 @@ READ_ONLY YES COMMAND_LINE_ARGUMENT REQUIRED VARIABLE_NAME INNODB_SPIN_WAIT_DELAY SESSION_VALUE NULL -DEFAULT_VALUE 6 +DEFAULT_VALUE 4 VARIABLE_SCOPE GLOBAL VARIABLE_TYPE INT UNSIGNED -VARIABLE_COMMENT Maximum delay between polling for a spin lock (6 by default) +VARIABLE_COMMENT Maximum delay between polling for a spin lock (4 by default) NUMERIC_MIN_VALUE 0 NUMERIC_MAX_VALUE 6000 NUMERIC_BLOCK_SIZE 0 |