From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
virtualization@lists.linux-foundation.org,
linux-s390@vger.kernel.org,
xen-devel-request@lists.xenproject.org, kvm@vger.kernel.org
Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
mingo@redhat.com, peterz@infradead.org,
paulmck@linux.vnet.ibm.com, will.deacon@arm.com,
kernellwp@gmail.com, jgross@suse.com, pbonzini@redhat.com,
bsingharora@gmail.com
Subject: Re: [PATCH v3 0/4] implement vcpu preempted check
Date: Wed, 5 Oct 2016 13:00:51 +0200 [thread overview]
Message-ID: <847f7377-61d3-835e-458b-aa9f4f5fcf8c@de.ibm.com> (raw)
In-Reply-To: <1469101514-49475-1-git-send-email-xinhui.pan@linux.vnet.ibm.com>
On 07/21/2016 01:45 PM, Pan Xinhui wrote:
> change from v2:
> no code change, fix typos, update some comments
>
> change from v1:
> a simplier definition of default vcpu_is_preempted
> skip mahcine type check on ppc, and add config. remove dedicated macro.
> add one patch to drop overload of rwsem_spin_on_owner and mutex_spin_on_owner.
> add more comments
> thanks boqun and Peter's suggestion.
>
> This patch set aims to fix lock holder preemption issues.
>
> test-case:
> perf record -a perf bench sched messaging -g 400 -p && perf report
>
> before patch:
> 18.09% sched-messaging [kernel.vmlinux] [k] osq_lock
> 12.28% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
> 5.27% sched-messaging [kernel.vmlinux] [k] mutex_unlock
> 3.89% sched-messaging [kernel.vmlinux] [k] wait_consider_task
> 3.64% sched-messaging [kernel.vmlinux] [k] _raw_write_lock_irq
> 3.41% sched-messaging [kernel.vmlinux] [k] mutex_spin_on_owner.is
> 2.49% sched-messaging [kernel.vmlinux] [k] system_call
>
> after patch:
> 9.99% sched-messaging [kernel.vmlinux] [k] mutex_unlock
> 5.28% sched-messaging [unknown] [H] 0xc0000000000768e0
> 4.27% sched-messaging [kernel.vmlinux] [k] __copy_tofrom_user_power7
> 3.77% sched-messaging [kernel.vmlinux] [k] copypage_power7
> 3.24% sched-messaging [kernel.vmlinux] [k] _raw_write_lock_irq
> 3.02% sched-messaging [kernel.vmlinux] [k] system_call
> 2.69% sched-messaging [kernel.vmlinux] [k] wait_consider_task
>
> We introduce interface bool vcpu_is_preempted(int cpu) and use it in some spin
> loops of osq_lock, rwsem_spin_on_owner and mutex_spin_on_owner.
> These spin_on_onwer variant also cause rcu stall before we apply this patch set
>
> Pan Xinhui (4):
> kernel/sched: introduce vcpu preempted check interface
> powerpc/spinlock: support vcpu preempted check
> locking/osq: Drop the overhead of osq_lock()
> kernel/locking: Drop the overhead of {mutex,rwsem}_spin_on_owner
>
> arch/powerpc/include/asm/spinlock.h | 18 ++++++++++++++++++
> include/linux/sched.h | 12 ++++++++++++
> kernel/locking/mutex.c | 15 +++++++++++++--
> kernel/locking/osq_lock.c | 10 +++++++++-
> kernel/locking/rwsem-xadd.c | 16 +++++++++++++---
> 5 files changed, 65 insertions(+), 6 deletions(-)
>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
for the full series. With my patch on top this really improves
some benchmarks for overcommitted KVM guests.
prev parent reply other threads:[~2016-10-05 11:01 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-21 11:45 [PATCH v3 0/4] implement vcpu preempted check Pan Xinhui
2016-07-21 11:45 ` [PATCH v3 1/4] kernel/sched: introduce vcpu preempted check interface Pan Xinhui
2016-07-21 11:45 ` [PATCH v3 2/4] powerpc/spinlock: support vcpu preempted check Pan Xinhui
2016-07-21 11:45 ` [PATCH v3 3/4] locking/osq: Drop the overhead of osq_lock() Pan Xinhui
2016-07-21 11:45 ` [PATCH v3 4/4] kernel/locking: Drop the overhead of {mutex, rwsem}_spin_on_owner Pan Xinhui
2016-09-29 10:10 ` [PATCH v3 0/4] implement vcpu preempted check Peter Zijlstra
2016-09-29 10:23 ` Christian Borntraeger
2016-09-29 10:31 ` Peter Zijlstra
2016-09-30 5:03 ` Pan Xinhui
2016-09-30 6:58 ` Paolo Bonzini
2016-09-30 8:52 ` Pan Xinhui
2016-09-30 9:08 ` Paolo Bonzini
2016-09-30 9:31 ` Pan Xinhui
2016-09-30 10:44 ` Christian Borntraeger
2016-09-29 10:40 ` Christian Borntraeger
2016-09-29 11:05 ` Christian Borntraeger
2016-09-30 4:00 ` Pan Xinhui
2016-10-05 11:00 ` Christian Borntraeger [this message]
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=847f7377-61d3-835e-458b-aa9f4f5fcf8c@de.ibm.com \
--to=borntraeger@de.ibm.com \
--cc=benh@kernel.crashing.org \
--cc=bsingharora@gmail.com \
--cc=jgross@suse.com \
--cc=kernellwp@gmail.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mingo@redhat.com \
--cc=mpe@ellerman.id.au \
--cc=paulmck@linux.vnet.ibm.com \
--cc=paulus@samba.org \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=virtualization@lists.linux-foundation.org \
--cc=will.deacon@arm.com \
--cc=xen-devel-request@lists.xenproject.org \
--cc=xinhui.pan@linux.vnet.ibm.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 NNTP newsgroup(s).