I run perf top during ./mtr testing and constantly see times()
function there. It's so slow, that it has no sense to run it
in a loop too many times.
This patch speeds up -suite=innodb for me from 218s to 208s.
9s of times() function!
Small postfix to MDEV-23175 to ensure faster option on FreeBSD
and compatibility to Solaris that isn't high resolution.
ftime is left as a backup in case an implementation doesn't
contain any of these clocks.
FreeBSD
$ ./unittest/mysys/my_rdtsc-t
1..11
# ----- Routine ---------------
# myt.cycles.routine : 5
# myt.nanoseconds.routine : 11
# myt.microseconds.routine : 13
# myt.milliseconds.routine : 11
# myt.ticks.routine : 17
# ----- Frequency -------------
# myt.cycles.frequency : 3610295566
# myt.nanoseconds.frequency : 1000000000
# myt.microseconds.frequency : 1000000
# myt.milliseconds.frequency : 899
# myt.ticks.frequency : 136
# ----- Resolution ------------
# myt.cycles.resolution : 1
# myt.nanoseconds.resolution : 1
# myt.microseconds.resolution : 1
# myt.milliseconds.resolution : 7
# myt.ticks.resolution : 1
# ----- Overhead --------------
# myt.cycles.overhead : 26
# myt.nanoseconds.overhead : 19140
# myt.microseconds.overhead : 19036
# myt.milliseconds.overhead : 578
# myt.ticks.overhead : 21544
ok 1 - my_timer_init() did not crash
ok 2 - The cycle timer is strictly increasing
ok 3 - The cycle timer is implemented
ok 4 - The nanosecond timer is increasing
ok 5 - The nanosecond timer is implemented
ok 6 - The microsecond timer is increasing
ok 7 - The microsecond timer is implemented
ok 8 - The millisecond timer is increasing
ok 9 - The millisecond timer is implemented
ok 10 - The tick timer is increasing
ok 11 - The tick timer is implemented
aarch64 timer is available to userspace via arch register.
clang's __builtin_readcyclecounter is wrong for aarch64 (reads the PMU
cycle counter instead of the archi-timer register), so we don't use it.
my_rdtsc unit-test on AWS m6g shows:
frequency: 121830845
resolution: 1
overhead: 1
This counter is not strictly increasing, but it is non-decreasing.
Linux glibc has deprecated ftime resutlting in a compile error on Fedora-32.
Per manual clock_gettime is the suggested replacement. Because my_timer_milliseconds
is a relative time used by largely the perfomrance schema, CLOCK_MONOTONIC_COARSE
is used. This has been available since Linux-2.6.32.
The low overhead is shows in the unittest:
$ unittest/mysys/my_rdtsc-t
1..11
# ----- Routine ---------------
# myt.cycles.routine : 5
# myt.nanoseconds.routine : 11
# myt.microseconds.routine : 13
# myt.milliseconds.routine : 18
# myt.ticks.routine : 17
# ----- Frequency -------------
# myt.cycles.frequency : 3596597014
# myt.nanoseconds.frequency : 1000000000
# myt.microseconds.frequency : 1000000
# myt.milliseconds.frequency : 1039
# myt.ticks.frequency : 103
# ----- Resolution ------------
# myt.cycles.resolution : 1
# myt.nanoseconds.resolution : 1
# myt.microseconds.resolution : 1
# myt.milliseconds.resolution : 1
# myt.ticks.resolution : 1
# ----- Overhead --------------
# myt.cycles.overhead : 118
# myt.nanoseconds.overhead : 234
# myt.microseconds.overhead : 222
# myt.milliseconds.overhead : 30
# myt.ticks.overhead : 4946
ok 1 - my_timer_init() did not crash
ok 2 - The cycle timer is strictly increasing
ok 3 - The cycle timer is implemented
ok 4 - The nanosecond timer is increasing
ok 5 - The nanosecond timer is implemented
ok 6 - The microsecond timer is increasing
ok 7 - The microsecond timer is implemented
ok 8 - The millisecond timer is increasing
ok 9 - The millisecond timer is implemented
ok 10 - The tick timer is increasing
ok 11 - The tick timer is implemented
On clang, use __builtin_readcyclecounter() when available.
Hinted by Sergey Vojtovich. (This may lead to runtime failure
on ARM systems. The hardware should be available on ARMv8 (AArch64),
but access to it may require special privileges.)
We remove support for the proprietary Sun Microsystems compiler,
and rely on clang or the __GNUC__ assembler syntax instead.
For now, we retain support for IA-64 (Itanium) and 32-bit SPARC,
even though those platforms are likely no longer widely used.
We remove support for clock_gettime(CLOCK_SGI_CYCLE),
because Silicon Graphics ceased supporting IRIX in December 2013.
This was the only cycle timer interface available for MIPS.
On PowerPC, we rely on the GCC 4.8 __builtin_ppc_get_timebase()
(or clang __builtin_readcyclecounter()), which should be equivalent
to the old assembler code on both 64-bit and 32-bit targets.
A few tests assumes that the CYCLE timer is always available,
which is not true on some platforms (e.g. ARM).
Fixing the tests not to reply on the CYCLE availability.
A few tests assumes that the CYCLE timer is always available,
which is not true on some platforms (e.g. ARM).
Fixing the tests not to reply on the CYCLE availability.
- Changed ER(ER_...) to ER_THD(thd, ER_...) when thd was known or if there was many calls to current_thd in the same function.
- Changed ER(ER_..) to ER_THD_OR_DEFAULT(current_thd, ER...) in some places where current_thd is not necessary defined.
- Removing calls to current_thd when we have access to thd
Part of this is optimization (not calling current_thd when not needed),
but part is bug fixing for error condition when current_thd is not defined
(For example on startup and end of mysqld)
Notable renames done as otherwise a lot of functions would have to be changed:
- In JOIN structure renamed:
examined_rows -> join_examined_rows
record_count -> join_record_count
- In Field, renamed new_field() to make_new_field()
Other things:
- Added DBUG_ASSERT(thd == tmp_thd) in Item_singlerow_subselect() just to be safe.
- Removed old 'tab' prefix in JOIN_TAB::save_explain_data() and use members directly
- Added 'thd' as argument to a few functions to avoid calling current_thd.
Remove some more leftovers from the initial removal:
o Update relevant mentions of configure.in throughout
the source code.
o Remove win/configure.js, which at this point just
duplicates logic already present in CMake based build
system.
o Remove support files which relied on the autotools
build system. In any case, MySQL is no longer officially
supported on SCO.
o Remove files which are no longer part of the build.