From: Sam Bobroff <sam.bobroff@au1.ibm.com>
To: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Cc: pbonzini@redhat.com, rkrcmar@redhat.com, agraf@suse.com,
corbet@lwn.net, paulus@samba.org, mpe@ellerman.id.au,
kvm@vger.kernel.org, kvm-ppc@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, benh@kernel.crashing.org,
linux-doc@vger.kernel.org
Subject: Re: [PATCH 0/6] kvm: powerpc halt polling updates
Date: Fri, 14 Oct 2016 14:28:47 +1100 [thread overview]
Message-ID: <20161014032847.GA27267@tungsten.ozlabs.ibm.com> (raw)
In-Reply-To: <1476406404-32752-1-git-send-email-sjitindarsingh@gmail.com>
On Fri, Oct 14, 2016 at 11:53:18AM +1100, Suraj Jitindar Singh wrote:
> This patch series makes some updates and bug fixes to the powerpc kvm-hv
> halt polling code.
>
> The first two patches are concerned with exporting the generic kvm module
> parameter variables and accessing these from the powerpc specific code.
>
> The third patch fixes a bug where changing the global max halt polling
> interval module parameter can sometimes have no effect.
>
> The fourth patch decreases the default global max halt polling interval
> to something more sensible.
>
> The fifth patch contains generic fixups with no functional effect.
>
> The last patch adds halt polling documentation.
>
> Suraj Jitindar Singh (6):
> kvm: export kvm module parameter variables
> powerpc/kvm: Use generic kvm module parameters in kvm-hv
> powerpc/kvm: Add check for module parameter halt_poll_ns
> powerpc/kvm: Decrease the powerpc default halt poll max value
> powerpc/kvm: Comment style and print format fixups
> doc/kvm: Add halt polling documentation
>
> Documentation/virtual/kvm/00-INDEX | 2 +
> Documentation/virtual/kvm/halt-polling.txt | 127 +++++++++++++++++++++++++++++
> arch/powerpc/include/asm/kvm_host.h | 2 +-
> arch/powerpc/kvm/book3s_hv.c | 33 ++------
> arch/powerpc/kvm/trace_hv.h | 2 +-
> include/linux/kvm_host.h | 4 +
> virt/kvm/kvm_main.c | 9 +-
> 7 files changed, 149 insertions(+), 30 deletions(-)
> create mode 100644 Documentation/virtual/kvm/halt-polling.txt
>
> --
> 2.5.5
Hi Suraj,
I've given this set a quick test and it seems to work fine. I used a repetitive
wakeup, using a nanosleep loop in guest userspace (with real time prio), and I
was able to cause halt polling to switch on and off as I adjusted halt_poll_ns.
I think the new default value is much better: halt polling started (e.g. CPU
utilization rose to 100%) once CPU utilization had already risen to about 75%.
Cheers,
Sam.
Tested-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
next prev parent reply other threads:[~2016-10-14 3:28 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-14 0:53 [PATCH 0/6] kvm: powerpc halt polling updates Suraj Jitindar Singh
2016-10-14 0:53 ` [PATCH 1/6] kvm: export kvm module parameter variables Suraj Jitindar Singh
2016-10-14 0:53 ` [PATCH 2/6] powerpc/kvm: Use generic kvm module parameters in kvm-hv Suraj Jitindar Singh
2016-10-14 0:53 ` [PATCH 3/6] powerpc/kvm: Add check for module parameter halt_poll_ns Suraj Jitindar Singh
2016-10-14 0:53 ` [PATCH 4/6] powerpc/kvm: Decrease the powerpc default halt poll max value Suraj Jitindar Singh
2016-10-14 0:53 ` [PATCH 5/6] powerpc/kvm: Comment style and print format fixups Suraj Jitindar Singh
2016-10-14 0:53 ` [PATCH 6/6] doc/kvm: Add halt polling documentation Suraj Jitindar Singh
2016-10-14 1:16 ` Wanpeng Li
2016-10-14 2:32 ` Suraj Jitindar Singh
2016-10-14 3:28 ` Sam Bobroff [this message]
2016-10-14 6:27 ` [PATCH 0/6] kvm: powerpc halt polling updates Nicholas Piggin
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=20161014032847.GA27267@tungsten.ozlabs.ibm.com \
--to=sam.bobroff@au1.ibm.com \
--cc=agraf@suse.com \
--cc=benh@kernel.crashing.org \
--cc=corbet@lwn.net \
--cc=kvm-ppc@vger.kernel.org \
--cc=kvm@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=paulus@samba.org \
--cc=pbonzini@redhat.com \
--cc=rkrcmar@redhat.com \
--cc=sjitindarsingh@gmail.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).