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Bug#21374104 SETUP_TIMERS INITIALIZATION ASSUMES CYCLE TIMER IS ALWAYS AVAILABLE

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For WAIT events, fall back to other timers if CYCLE is not available.
This commit is contained in:
Christopher Powers 2015-07-10 20:42:33 +02:00
parent c773b320ff
commit 49667f0441
3 changed files with 45 additions and 4 deletions
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4
mysql-test/suite/perfschema/r/query_cache.result
View File

@ -38,7 +38,7 @@ spins
NULL
select * from performance_schema.setup_timers where name='wait';
NAME TIMER_NAME
wait CYCLE
wait {CYCLE_OR_NANOSECOND}
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
@ -53,7 +53,7 @@ spins
NULL
select * from performance_schema.setup_timers where name='wait';
NAME TIMER_NAME
wait CYCLE
wait {CYCLE_OR_NANOSECOND}
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1

2
mysql-test/suite/perfschema/t/query_cache.test
View File

@ -34,6 +34,7 @@ show status like "Qcache_hits";
select spins from performance_schema.events_waits_current order by event_name limit 1;
--replace_result CYCLE {CYCLE_OR_NANOSECOND} NANOSECOND {CYCLE_OR_NANOSECOND}
select * from performance_schema.setup_timers where name='wait';
show status like "Qcache_queries_in_cache";
@ -42,6 +43,7 @@ show status like "Qcache_hits";
select spins from performance_schema.events_waits_current order by event_name limit 1;
--replace_result CYCLE {CYCLE_OR_NANOSECOND} NANOSECOND {CYCLE_OR_NANOSECOND}
select * from performance_schema.setup_timers where name='wait';
show status like "Qcache_queries_in_cache";

43
storage/perfschema/pfs_timer.cc
View File

@ -1,5 +1,4 @@
/* Copyright (c) 2008 MySQL AB, 2010 Sun Microsystems, Inc.
Use is subject to license terms.
/* Copyright (c) 2008, 2015, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@ -89,6 +88,46 @@ void init_timers(void)
(double)pfs_timer_info.ticks.frequency);
else
tick_to_pico= 0;
/*
Depending on the platform and build options, some timers may not be
available. Pick best replacements.
*/
/*
For WAIT, the cycle timer is used by default. However, it is not available
on all architectures. Fall back to the nanosecond timer in this case. It is
unlikely that neither cycle nor nanosecond are available, but we continue
probing less resolution timers anyway for consistency with other events.
*/
if (cycle_to_pico != 0)
{
/* Normal case. */
wait_timer= TIMER_NAME_CYCLE;
}
else if (nanosec_to_pico != 0)
{
/* Robustness, no known cases. */
wait_timer= TIMER_NAME_NANOSEC;
}
else if (microsec_to_pico != 0)
{
/* Robustness, no known cases. */
wait_timer= TIMER_NAME_MICROSEC;
}
else if (millisec_to_pico != 0)
{
/* Robustness, no known cases. */
wait_timer= TIMER_NAME_MILLISEC;
}
else
{
/*
Will never be reached on any architecture, but must provide a default if
no other timers are available.
*/
wait_timer= TIMER_NAME_TICK;
}
}
ulonglong get_timer_value(enum_timer_name timer_name)