…/kernel syscalls, which will in turn result in contention on kernel_mutex (trx_sys->mutex in 5.6), as memory allocation occurs under that mutex…
Post: Memory allocators: MySQL performance improvements in Percona Server 5.5.30-30.2
April 15, 2013 By
Post: trx descriptors: MySQL performance improvements in Percona Server 5.5.30-30.2
April 12, 2013 By 3 Comments
… under kernel_mutex (or trx_sys->mutex in 5.6) and that is one of the top reasons for contention on that mutex. Percona…
Post: kernel_mutex problem. Or double throughput with single variable
December 2, 2011 By 17 Comments
… ALL active transactions, and this loop is inside kernel_mutex. That is to see kernel_mutex in action, we need many concurrent but short….c line 1184 for 0.0000 seconds the semaphore: Mutex at 0x2b0ccc8 ‘&kernel_mutex‘, lock var 1 waiters flag 0 –Thread 140370752542464 has… recall that kernel_mutex (and all InnoDB mutexes) has complex handling with spin loops, and there are two variables that affects mutex loops: innodb…
Post: kernel_mutex problem cont. Or triple your throughput
December 2, 2011 By 10 Comments
This is to follow up my previous post with kernel_mutex problem. First, I may have an explanation why the performance … the performance degradation is following: InnoDB still uses some strange mutex implementation, based on sync_arrays (hello 1990ies), I do not…, and on pthread_cond_broadcast call, all threads, competing on mutex, wake up and start racing. This effect has name thundering…
Comment: Returning to InnoDB scalability
September 13, 2006 By 42 Comments
…_monitor_mutex | srv0srv.c | 21679 | 8 | 80 | 4 | 4 | 0 | | &kernel_mutex | srv0srv.c | 931679981 | 51334 | 347827 | 10652 | 13328 | 0 | | &thr_local_mutex | thr0loc…_monitor_mutex | srv0srv.c | 5913 | 2 | 20 | 1 | 1 | 0 | | &kernel_mutex | srv0srv.c | 512322207 | 3876530 | 19052043 | 148193 | 266380 | 0 | | &thr_local_mutex | thr0loc…
Comment: Returning to InnoDB scalability
August 4, 2006 By 42 Comments
…_monitor_mutex | srv0srv.c | 57877 | 0 | 0 | 0 | 0 | 0 | | &kernel_mutex | srv0srv.c | 8326330740 | 17826281 | 130886065 | 1071867 | 2746135 | 0 | | &thr_local_mutex | thr0loc.c | 811915 | 0 | 0 | 0 | 0 | 0 | | &(pool->mutex) | mem0pool…
Comment: Returning to InnoDB scalability
August 10, 2006 By 42 Comments
…_monitor_mutex | srv0srv.c | 5757 | 0 | 0 | 0 | 0 | 0 | | &kernel_mutex | srv0srv.c | 778621669 | 2111798 | 14420357 | 122435 | 306187 | 0 | | &thr_local_mutex | thr0loc.c | 78340 | 0 | 0 | 0 | 0 | 0 | | &(pool->mutex) | mem0pool…
Post: Announcing Percona Server for MySQL version 5.5.29-30.0
February 26, 2013 By Leave a Comment
… its adaptive flushing decisions. Fixed by acquiring the flush list mutex around the list scans. Bug fixed #1083058 (Laurynas Biveinis). Upstream… without taking the kernel mutex. Thus any list element might become invalid during its iteration. Fixed by taking the kernel mutex. Bug fixed #1101030…
Post: Tuning for heavy writing workloads
October 14, 2009 By 9 Comments
…” in the graph is the perfomance. We can confirm the mutex/lock contention roughly by the SEMAPHORES sction of SHOW INNODB….c line 167″ may be remarkable (it is rseg->mutex). The mutex is for each rollback segments, so we can increase the… next contention may be “Mutex at 0x28ce8e0 created file srv/srv0srv.c line 982″. It is kernel_mutex, currently we don’t have…
Comment: Three ways that the poor man's profiler can hurt MySQL
December 2, 2011 By 19 Comments
…/kernel_mutex-problem-or-double-throughput-with-single-variable/ by the way, Vadim and I discussed and he did some followup work. kernel_mutex…
