Re: Deadlock in XLogInsert at AIX
REIX, Tony <tony.reix@atos.net>
From: "REIX, Tony" <tony.reix@atos.net>
To: Konstantin Knizhnik <k.knizhnik@postgrespro.ru>,
PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Bernd Helmle <mailings@oopsware.de>
Date: 2017-02-01T13:29:33Z
Lists: pgsql-hackers
Hi,
I'm now working on the port of PostgreSQL on AIX.
(RPMs can be found, as free OpenSource work, at http://http://bullfreeware.com/ .
http://bullfreeware.com/search.php?package=postgresql )
I was not aware of any issue with XLC v12 on AIX for atomic operations.
(XLC v13 generates at least 2 tests failures)
For now, with version 9.6.1, all tests "check-world", plus numeric_big test, are OK, in both 32 & 64bit versions.
Am I missing something ?
I configure the build of PostgreSQL with (in 64bits):
./configure
--prefix=/opt/freeware
--libdir=/opt/freeware/lib64
--mandir=/opt/freeware/man
--with-perl
--with-tcl
--with-tclconfig=/opt/freeware/lib
--with-python
--with-ldap
--with-openssl
--with-libxml
--with-libxslt
--enable-nls
--enable-thread-safety
--sysconfdir=/etc/sysconfig/postgresql
Am I missing some option for more optimization on AIX ?
Thanks
Regards,
Tony
Le 01/02/2017 à 12:07, Konstantin Knizhnik a écrit :
Attached please find my patch for XLC/AIX.
The most critical fix is adding __sync to pg_atomic_fetch_add_u32_impl.
The comment in this file says that:
* __fetch_and_add() emits a leading "sync" and trailing "isync",
thereby
* providing sequential consistency. This is undocumented.
But it is not true any more (I checked generated assembler code in
debugger).
This is why I have added __sync() to this function. Now pgbench working
normally.
Also there is mysterious disappearance of assembler section function
with sync instruction from pg_atomic_compare_exchange_u32_impl.
I have fixed it by using __sync() built-in function instead.
Thanks to everybody who helped me to locate and fix this problem.
--
Konstantin Knizhnik
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
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Commits
-
For all ppc compilers, implement compare_exchange and fetch_add with asm.
- 30ee5d17c20d 13.0 landed
-
For PowerPC instruction "addi", use constraint "b".
- 930787c7fab9 9.4.25 landed
- af4477b00cf9 11.6 landed
- 62e881946c4d 9.5.20 landed
- 09d74aef33de 9.6.16 landed
- 083929372e04 10.11 landed
- ef13f914e6c2 12.1 landed
- 89b4d7744c80 13.0 landed
-
For all ppc compilers, implement pg_atomic_fetch_add_ with inline asm.
- e7ff59686eac 13.0 landed
-
Replace xlc __fetch_and_add() with inline asm.
- a1df9a015dac 9.6.16 landed
- 8972ac696665 10.11 landed
- 75941f257aac 9.5.20 landed
- 40ad4202513c 11.6 landed
- 1c6b62a7d0e5 12.0 landed
- dd50f1a43290 13.0 landed
-
Test pg_atomic_fetch_add_ with variable addend and 16-bit edge cases.
- e6a90ded5a6c 10.11 landed
- 8d32f82cbbbb 9.6.16 landed
- 4737d3a75b72 9.5.20 landed
- 5b5b0f721d9c 12.0 landed
- 585fc561f824 11.6 landed
- f380c5190134 13.0 landed