Using __ppc_get_timebase will translate to mfspr instruction
The mfspr instruction will block FXU1 until complete but the other
Pipelines are available for execution of instructions from other
SMT threads on the same core.
The latency time to read the timebase SPR is ~10 cycles.
So any impact on other threads is limited other FXU1 only instructions
(basically other mfspr/mtspr ops).
Suggested by Steven J. Munroe, Linux on Power Toolchain Architect,
Linux Technology Center
IBM Corporation
Bug#18842925 : SET THREAD PRIORITY IN INNODB MUTEX SPINLOOP
Like "pause" instruction for hyper-threading at Intel CPUs,
POWER has special instructions only for hinting priority of hardware-threads.
Approved by Sunny in rb#6256
Backport of the 5.7 fix - c92102a6ef
(excluded cache line size patch)
Suggestion by Stewart Smith
UT_RELAX_CPU(): Use a compiler barrier.
ut_delay(): Remove the dummy global variable ut_always_false.
RB: 11399
Reviewed-by: Jimmy Yang <jimmy.yang@oracle.com>
Backported from MySQL-5.7 - patch 5e3efb0396
Suggestion by Stewart Smith
support ha_innodb.so as a dynamic plugin.
* remove obsolete *,innodb_plugin.rdiff files
* s/--plugin-load=/--plugin-load-add=/
* MYSQL_PLUGIN_IMPORT glob_hostname[]
* use my_error instead of push_warning_printf(ER_DEFAULT)
* don't use tdc_size and tc_size in a module
update test cases (XtraDB is 5.6.14, InnoDB is 5.6.10)
* copy new tests over
* disable some tests for (old) InnoDB
* delete XtraDB tests that no longer apply
small compatibility changes:
* s/HTON_EXTENDED_KEYS/HTON_SUPPORTS_EXTENDED_KEYS/
* revert unnecessary InnoDB changes to make it a bit closer to the upstream
fix XtraDB to compile on Windows (both as a static and a dynamic plugin)
disable XtraDB on Windows (deadlocks) and where no atomic ops are available (e.g. CentOS 5)
storage/innobase/handler/ha_innodb.cc:
revert few unnecessary changes to make it a bit closer to the original InnoDB
storage/innobase/include/univ.i:
correct the version to match what it was merged from
- Use native memcmp() supplied with C runtime instead of hand-unrolled loop ptr_compare_N loop
Prior to fix ptr_compare_0() has 3.7% samples in OLTP-RO in-memory.
Fix brings this down to 1.8% (all memcmp samples)
- Innodb : fix UT_RELAX_CPU to be defined as YieldProcessor, as was also originally intended
(but intention was lost in the #ifdef maze
This reduces number of ut_delay() samples in profile from 1.5% to 0.5%
