From: Yury Norov <ynorov@caviumnetworks.com> To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Yury Norov <ynorov@caviumnetworks.com>, Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, Arnd Bergmann <arnd@arndb.de>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com>, Jan Glauber <jglauber@cavium.com> Subject: [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks Date: Tue, 11 Apr 2017 01:35:01 +0400 [thread overview] Message-ID: <1491860104-4103-1-git-send-email-ynorov@caviumnetworks.com> (raw) The patch of Jan Glauber enables queued spinlocks on arm64. I rebased it on latest kernel sources, and added a couple of fixes to headers to apply it smoothly. Though, locktourture test shows significant performance degradation in the acquisition of rw-lock for read on qemu: Before After spin_lock-torture: 38957034 37076367 -4.83 rw_lock-torture W: 5369471 18971957 253.33 rw_lock-torture R: 6413179 3668160 -42.80 I'm not much experienced in locking, and so wonder how it's possible that simple switching to generic queued rw-lock causes so significant performance degradation, while in theory it should improve it. Even more, on x86 there are no such problems probably. I also think that patches 1 and 2 are correct and useful, and should be applied anyway. Any comments appreciated. Yury. Jan Glauber (1): arm64/locking: qspinlocks and qrwlocks support Yury Norov (2): kernel/locking: #include <asm/spinlock.h> in qrwlock.c asm-generic: don't #include <linux/atomic.h> in qspinlock_types.h arch/arm64/Kconfig | 2 ++ arch/arm64/include/asm/qrwlock.h | 7 +++++++ arch/arm64/include/asm/qspinlock.h | 20 ++++++++++++++++++++ arch/arm64/include/asm/spinlock.h | 12 ++++++++++++ arch/arm64/include/asm/spinlock_types.h | 14 +++++++++++--- include/asm-generic/qspinlock.h | 1 + include/asm-generic/qspinlock_types.h | 8 -------- kernel/locking/qrwlock.c | 1 + 8 files changed, 54 insertions(+), 11 deletions(-) create mode 100644 arch/arm64/include/asm/qrwlock.h create mode 100644 arch/arm64/include/asm/qspinlock.h -- 2.7.4
WARNING: multiple messages have this Message-ID (diff)
From: ynorov@caviumnetworks.com (Yury Norov) To: linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks Date: Tue, 11 Apr 2017 01:35:01 +0400 [thread overview] Message-ID: <1491860104-4103-1-git-send-email-ynorov@caviumnetworks.com> (raw) The patch of Jan Glauber enables queued spinlocks on arm64. I rebased it on latest kernel sources, and added a couple of fixes to headers to apply it smoothly. Though, locktourture test shows significant performance degradation in the acquisition of rw-lock for read on qemu: Before After spin_lock-torture: 38957034 37076367 -4.83 rw_lock-torture W: 5369471 18971957 253.33 rw_lock-torture R: 6413179 3668160 -42.80 I'm not much experienced in locking, and so wonder how it's possible that simple switching to generic queued rw-lock causes so significant performance degradation, while in theory it should improve it. Even more, on x86 there are no such problems probably. I also think that patches 1 and 2 are correct and useful, and should be applied anyway. Any comments appreciated. Yury. Jan Glauber (1): arm64/locking: qspinlocks and qrwlocks support Yury Norov (2): kernel/locking: #include <asm/spinlock.h> in qrwlock.c asm-generic: don't #include <linux/atomic.h> in qspinlock_types.h arch/arm64/Kconfig | 2 ++ arch/arm64/include/asm/qrwlock.h | 7 +++++++ arch/arm64/include/asm/qspinlock.h | 20 ++++++++++++++++++++ arch/arm64/include/asm/spinlock.h | 12 ++++++++++++ arch/arm64/include/asm/spinlock_types.h | 14 +++++++++++--- include/asm-generic/qspinlock.h | 1 + include/asm-generic/qspinlock_types.h | 8 -------- kernel/locking/qrwlock.c | 1 + 8 files changed, 54 insertions(+), 11 deletions(-) create mode 100644 arch/arm64/include/asm/qrwlock.h create mode 100644 arch/arm64/include/asm/qspinlock.h -- 2.7.4
next reply other threads:[~2017-04-10 21:35 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-04-10 21:35 Yury Norov [this message] 2017-04-10 21:35 ` [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks Yury Norov 2017-04-10 21:35 ` [PATCH 1/3] kernel/locking: #include <asm/spinlock.h> in qrwlock.c Yury Norov 2017-04-10 21:35 ` Yury Norov 2017-04-10 21:35 ` [PATCH 2/3] asm-generic: don't #include <linux/atomic.h> in qspinlock_types.h Yury Norov 2017-04-10 21:35 ` Yury Norov 2017-04-10 21:35 ` [PATCH 3/3] arm64/locking: qspinlocks and qrwlocks support Yury Norov 2017-04-10 21:35 ` Yury Norov 2017-04-13 18:12 ` Peter Zijlstra 2017-04-13 18:12 ` Peter Zijlstra 2017-04-20 18:23 ` Yury Norov 2017-04-20 18:23 ` Yury Norov 2017-04-20 19:00 ` Mark Rutland 2017-04-20 19:00 ` Mark Rutland 2017-04-20 19:05 ` Peter Zijlstra 2017-04-20 19:05 ` Peter Zijlstra 2017-04-26 12:39 ` Yury Norov 2017-04-26 12:39 ` Yury Norov 2017-04-28 15:44 ` Will Deacon 2017-04-28 15:44 ` Will Deacon 2017-04-12 17:04 ` [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks Adam Wallis 2017-04-12 17:04 ` Adam Wallis 2017-04-13 10:33 ` Yury Norov 2017-04-13 10:33 ` Yury Norov 2017-04-28 15:37 ` Will Deacon 2017-04-28 15:37 ` Will Deacon 2017-04-24 13:36 ` Will Deacon 2017-04-24 13:36 ` Will Deacon
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=1491860104-4103-1-git-send-email-ynorov@caviumnetworks.com \ --to=ynorov@caviumnetworks.com \ --cc=arnd@arndb.de \ --cc=catalin.marinas@arm.com \ --cc=jglauber@cavium.com \ --cc=linux-arch@vger.kernel.org \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-kernel@vger.kernel.org \ --cc=mingo@redhat.com \ --cc=peterz@infradead.org \ --cc=will.deacon@arm.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: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.