From: Maxim Kuvyrkov <maxim@codesourcery.com>
To: "Joseph S. Myers" <joseph@codesourcery.com>
Cc: Richard Sandiford <rdsandiford@googlemail.com>,
<libc-ports@sourceware.org>
Subject: [PATCH 2/3, MIPS] Rewrite MIPS' pthread_spin_[try]lock using __atomic_* builtins.
Date: Thu, 14 Jun 2012 04:36:00 -0000 [thread overview]
Message-ID: <2109EAD5-BBE8-4C8C-8D61-0AF33290F240@codesourcery.com> (raw)
This is a follow-up patch to convert assembly implementations of MIPS' pthread_spin_[try]lock routines using __atomic_* builtins. Using the builtins the compiler can generate optimal code for a particular MIPS processor for which GLIBC is being built.
OK to apply once 2.16 branches?
Thank you,
--
Maxim Kuvyrkov
CodeSourcery / Mentor Graphics
2012-06-13 Tom de Vries <vries@codesourcery.com>
Maxim Kuvyrkov <maxim@codesourcery.com>
* sysdeps/mips/nptl/pthread_spin_[try]lock.S: Remove.
* sysdeps/mips/nptl/pthread_spin_[try]lock.c: New files.
---
sysdeps/mips/nptl/pthread_spin_lock.S | 36 -------------------------
sysdeps/mips/nptl/pthread_spin_lock.c | 43 ++++++++++++++++++++++++++++++
sysdeps/mips/nptl/pthread_spin_trylock.S | 40 ---------------------------
sysdeps/mips/nptl/pthread_spin_trylock.c | 26 ++++++++++++++++++
4 files changed, 69 insertions(+), 76 deletions(-)
delete mode 100644 sysdeps/mips/nptl/pthread_spin_lock.S
create mode 100644 sysdeps/mips/nptl/pthread_spin_lock.c
delete mode 100644 sysdeps/mips/nptl/pthread_spin_trylock.S
create mode 100644 sysdeps/mips/nptl/pthread_spin_trylock.c
diff --git a/sysdeps/mips/nptl/pthread_spin_lock.S b/sysdeps/mips/nptl/pthread_spin_lock.S
deleted file mode 100644
index a8504f1..0000000
--- a/sysdeps/mips/nptl/pthread_spin_lock.S
+++ /dev/null
@@ -1,36 +0,0 @@
-/* Copyright (C) 2005 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
-
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
-
- The GNU C Library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library. If not, see
- <http://www.gnu.org/licenses/>. */
-
-#include <sys/asm.h>
-#include <sysdep.h>
-#include <sgidefs.h>
-
-ENTRY (pthread_spin_lock)
- .set push
-#if _MIPS_SIM == _ABIO32
- .set mips2
-#endif
-1: ll a2, 0(a0)
- li a1, 1
- bnez a2, 1b
- sc a1, 0(a0)
- beqz a1, 1b
- MIPS_SYNC
- .set pop
- li v0, 0
- ret
-PSEUDO_END (pthread_spin_lock)
diff --git a/sysdeps/mips/nptl/pthread_spin_lock.c b/sysdeps/mips/nptl/pthread_spin_lock.c
new file mode 100644
index 0000000..42dcb8d
--- /dev/null
+++ b/sysdeps/mips/nptl/pthread_spin_lock.c
@@ -0,0 +1,43 @@
+/* Copyright (C) 2012 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If
+ not, see <http://www.gnu.org/licenses/>. */
+
+#include <atomic.h>
+#include "pthreadP.h"
+
+int
+pthread_spin_lock (pthread_spinlock_t *lock)
+{
+
+ /* atomic_exchange takes less instructions than atomic_compare_and_exchange
+ for MIPS, in particular when the MIPS ISA supports an atomic exchange
+ instruction. On the other hand, atomic_exchange potentially generates more
+ bus traffic in case the value already present is written back.
+ We assume that the first try mostly will be successful, so we use
+ atomic_exchange. For the other tries, we use
+ atomic_compare_and_exchange. */
+ if (atomic_exchange_acq (lock, 1) == 0)
+ return 0;
+
+ do
+ {
+ while (*lock != 0)
+ ;
+ }
+ while (atomic_compare_and_exchange_val_acq (lock, 1, 0) != 0);
+
+ return 0;
+}
diff --git a/sysdeps/mips/nptl/pthread_spin_trylock.S b/sysdeps/mips/nptl/pthread_spin_trylock.S
deleted file mode 100644
index 95b55c3..0000000
--- a/sysdeps/mips/nptl/pthread_spin_trylock.S
+++ /dev/null
@@ -1,40 +0,0 @@
-/* Copyright (C) 2005 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
-
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
-
- The GNU C Library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library. If not, see
- <http://www.gnu.org/licenses/>. */
-
-#include <sys/asm.h>
-#include <sysdep.h>
-#define _ERRNO_H 1
-#include <bits/errno.h>
-#include <sgidefs.h>
-
-ENTRY (pthread_spin_trylock)
- .set push
-#if _MIPS_SIM == _ABIO32
- .set mips2
-#endif
- ll a2, 0(a0)
- li a1, 1
- bnez a2, 1f
- sc a1, 0(a0)
- beqz a1, 1f
- MIPS_SYNC
- .set pop
- li v0, 0
- ret
-1: li v0, EBUSY
- ret
-PSEUDO_END (pthread_spin_trylock)
diff --git a/sysdeps/mips/nptl/pthread_spin_trylock.c b/sysdeps/mips/nptl/pthread_spin_trylock.c
new file mode 100644
index 0000000..ed75813
--- /dev/null
+++ b/sysdeps/mips/nptl/pthread_spin_trylock.c
@@ -0,0 +1,26 @@
+/* Copyright (C) 2012 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If
+ not, see <http://www.gnu.org/licenses/>. */
+
+#include <errno.h>
+#include <atomic.h>
+#include "pthreadP.h"
+
+int
+pthread_spin_trylock (pthread_spinlock_t *lock)
+{
+ return atomic_compare_and_exchange_val_acq (lock, 1, 0) ? EBUSY : 0;
+}
--
1.7.4.1
next reply other threads:[~2012-06-14 4:36 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-14 4:36 Maxim Kuvyrkov [this message]
2012-06-28 23:10 ` Joseph S. Myers
2012-07-11 5:58 ` [PATCH] Unify pthread_spin_[try]lock implementations Maxim Kuvyrkov
2012-07-11 8:15 ` Roland McGrath
2012-07-11 8:25 ` David Miller
2012-07-11 8:44 ` Andrew Haley
2012-07-11 8:54 ` Maxim Kuvyrkov
2012-07-11 9:02 ` Andrew Haley
2012-07-11 9:05 ` Maxim Kuvyrkov
2012-07-11 11:22 ` Roland McGrath
2012-07-11 14:52 ` Chris Metcalf
2012-07-11 22:16 ` Maxim Kuvyrkov
2012-07-25 18:13 ` Roland McGrath
2012-07-25 19:04 ` Chris Metcalf
2012-07-25 20:22 ` Roland McGrath
2012-07-25 20:29 ` Chris Metcalf
2012-07-25 20:43 ` Roland McGrath
2012-08-15 3:17 ` Maxim Kuvyrkov
2012-08-15 16:27 ` Roland McGrath
2012-08-15 16:39 ` Maxim Kuvyrkov
2012-08-15 16:44 ` Roland McGrath
2012-08-15 16:53 ` Maxim Kuvyrkov
2012-08-15 16:56 ` Roland McGrath
2012-08-15 17:05 ` Maxim Kuvyrkov
2012-08-15 17:05 ` Jeff Law
2012-08-15 17:11 ` Roland McGrath
2012-08-15 17:24 ` Jeff Law
2012-08-15 16:40 ` Joseph S. Myers
2012-08-15 16:43 ` Carlos O'Donell
2012-08-15 22:00 ` Andreas Schwab
2012-08-16 10:21 ` Torvald Riegel
2012-08-16 12:40 ` Chris Metcalf
2012-08-22 23:16 ` Maxim Kuvyrkov
2012-07-11 8:26 ` Maxim Kuvyrkov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2109EAD5-BBE8-4C8C-8D61-0AF33290F240@codesourcery.com \
--to=maxim@codesourcery.com \
--cc=joseph@codesourcery.com \
--cc=libc-ports@sourceware.org \
--cc=rdsandiford@googlemail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).