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  1. MariaDB Server
  2. MDEV-6533

MySQL Bug#72718 - CACHE_LINE_SIZE in innodb should be 128 on POWER

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          Description

          The following patch is suggested by Stewart Smith:

          Define CACHE_LINE_SIZE in ut0counter.h to 128 on POWER

Index: mysql-5.6.17/storage/innobase/include/ut0counter.h
===================================================================
--- mysql-5.6.17.orig/storage/innobase/include/ut0counter.h
+++ mysql-5.6.17/storage/innobase/include/ut0counter.h
@@ -32,7 +32,11 @@ Created 2012/04/12 by Sunny Bains
 #include "os0thread.h"

 /** CPU cache line size */
+#ifdef __powerpc__
+#define CACHE_LINE_SIZE                128
+#else
 #define CACHE_LINE_SIZE                64
+#endif

 /** Default number of slots to use in ib_counter_t */
 #define IB_N_SLOTS             64

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                Task - A task that needs to be done. MDEV-6530 Examine and apply Power8 patches suggested by Stewart Smith

                • Major - Major loss of function.
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                Web Link MySQL BUG#72718

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                  svoj Sergey Vojtovich added a comment -

                  We need to double check proper way of determining CPU cache line size. Plus XtraDB had one more source file with CACHE_LINE_SIZE definition/

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                  svoj Sergey Vojtovich added a comment - We need to double check proper way of determining CPU cache line size. Plus XtraDB had one more source file with CACHE_LINE_SIZE definition/
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                  monty Michael Widenius added a comment -

                  ok to push for now
                  Just add to the comment that the change was suggested by stewart smith.

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                  monty Michael Widenius added a comment - ok to push for now Just add to the comment that the change was suggested by stewart smith.
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                  monty Michael Widenius added a comment -

                  ok to push after comment change

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                  monty Michael Widenius added a comment - ok to push after comment change
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                  svoj Sergey Vojtovich added a comment -

                  Adjusting cache line size is the right thing in theory. But in practice we didn't see any noteworthy throughput increase with this patch. We'll get back to this patch when we have proof that smaller cache line size negatively affects performance.

                  Show
                  svoj Sergey Vojtovich added a comment - Adjusting cache line size is the right thing in theory. But in practice we didn't see any noteworthy throughput increase with this patch. We'll get back to this patch when we have proof that smaller cache line size negatively affects performance.
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                  svoj Sergey Vojtovich added a comment -

                  Axel reported that this patch gives ~5% throughput increase @ 20cores.

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                  svoj Sergey Vojtovich added a comment - Axel reported that this patch gives ~5% throughput increase @ 20cores.
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                  svoj Sergey Vojtovich added a comment - 
                  revno: 4427
revision-id: svoj@mariadb.org-20141003133846-h7cjr7mbk653q450
parent: bar@mnogosearch.org-20141002114820-2jqqgtje33dx4679
committer: Sergey Vojtovich <svoj@mariadb.org>
branch nick: 10.0-mdev6533
timestamp: Fri 2014-10-03 17:38:46 +0400
message:
  MDEV-6533 - MySQL Bug#72718 - CACHE_LINE_SIZE in innodb should be 128 on POWER

  This patch is suggested by Stewart Smith.
  Define CACHE_LINE_SIZE to 128 on POWER.
                  Show
                  svoj Sergey Vojtovich added a comment - revno: 4427 revision-id: svoj@mariadb.org-20141003133846-h7cjr7mbk653q450 parent: bar@mnogosearch.org-20141002114820-2jqqgtje33dx4679 committer: Sergey Vojtovich <svoj@mariadb.org> branch nick: 10.0-mdev6533 timestamp: Fri 2014-10-03 17:38:46 +0400 message: MDEV-6533 - MySQL Bug#72718 - CACHE_LINE_SIZE in innodb should be 128 on POWER This patch is suggested by Stewart Smith. Define CACHE_LINE_SIZE to 128 on POWER.

                    People

                    • Assignee:
                      svoj Sergey Vojtovich
                      Reporter:
                      svoj Sergey Vojtovich
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                        Updated:
                        Resolved: