From: Davi Arnaut
Date: October 1 2008 12:24pm
Subject: bzr commit into mysql-5.1 branch (davi:2693) Bug#35164 Bug#37536
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X-Bug: 35164,37536
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# At a local mysql-5.1 repository of davi

 2693 Davi Arnaut	2008-10-01
      Bug#35164: Large number of invalid pthread_attr_setschedparam calls
      Bug#37536: Thread scheduling causes performance degradation at low thread count
      
      Deprecated --skip-thread-priority startup option as newer versions of
      the server won't change the thread priorities by default.
      
      Giving threads different priorities might yield marginal improvements
      in some platforms (where it actually works) but on the other hand it
      might cause significant degradation depending on the thread count and
      number of processors. Meddling with the thread priorities is a not a
      safe bet as it is very dependent on the behavior of the cpu scheduler
      and system where MySQL is being run.
      
      From MySQL 6.0 and up the default behavior is that of not modifying
      the threads priorities.
modified:
  sql/mysqld.cc

per-file messages:
  sql/mysqld.cc
    Deprecate --skip-thread-priority
=== modified file 'sql/mysqld.cc'
--- a/sql/mysqld.cc	2008-09-29 13:53:40 +0000
+++ b/sql/mysqld.cc	2008-10-01 12:24:35 +0000
@@ -6223,7 +6223,7 @@ Can't be set to 1 if --log-slave-updates
   {"skip-symlink", OPT_SKIP_SYMLINKS, "Don't allow symlinking of tables. Deprecated option.  Use --skip-symbolic-links instead.",
    0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
   {"skip-thread-priority", OPT_SKIP_PRIOR,
-   "Don't give threads different priorities.", 0, 0, 0, GET_NO_ARG, NO_ARG,
+   "Don't give threads different priorities. Deprecated option.", 0, 0, 0, GET_NO_ARG, NO_ARG,
    DEFAULT_SKIP_THREAD_PRIORITY, 0, 0, 0, 0, 0},
 #ifdef HAVE_REPLICATION
   {"slave-load-tmpdir", OPT_SLAVE_LOAD_TMPDIR,
@@ -7865,6 +7865,9 @@ mysqld_get_one_option(int optid,
     break;
   case (int) OPT_SKIP_PRIOR:
     opt_specialflag|= SPECIAL_NO_PRIOR;
+    sql_print_warning("The --skip-thread-priority startup option is deprecated "
+                      "and will be removed in MySQL 7.0. MySQL 6.0 and up do not "
+                      "give threads different priorities.");
     break;
   case (int) OPT_SKIP_LOCK:
     opt_external_locking=0;