From: Jingyi Wang <wangjingyi11@huawei.com>
To: Marc Zyngier <maz@kernel.org>
Cc: kvm@vger.kernel.org, catalin.marinas@arm.com,
fanhenglong@huawei.com, prime.zeng@hisilicon.com,
will@kernel.org, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 0/4] Add support for ARMv8.6 TWED feature
Date: Wed, 30 Sep 2020 09:21:30 +0800 [thread overview]
Message-ID: <21241889-7fca-5cd3-a5d3-41eb34f9c960@huawei.com> (raw)
In-Reply-To: <913250ae919fb9453feadd0527827d55@kernel.org>
Hi Marc,
On 9/29/2020 6:50 PM, Marc Zyngier wrote:
> On 2020-09-29 10:17, Jingyi Wang wrote:
>> TWE Delay is an optional feature in ARMv8.6 Extentions. There is a
>> performance benefit in waiting for a period of time for an event to
>> arrive before taking the trap as it is common that event will arrive
>> “quite soon” after executing the WFE instruction.
>
> Define "quite soon". Quantify "performance benefits". Which are the
> workloads that actually benefit from this imitation of the x86 PLE?
>
> I was opposed to this when the spec was drafted, and I still am given
> that there is zero supporting evidence that it bring any gain over
> immediate trapping in an oversubscribed environment (which is the only
> case where it matters).
>
> Thanks,
>
> M.
Sure, I will do more performance tests and post the results as soon as
possible.
Thanks,
Jingyi
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
next prev parent reply other threads:[~2020-09-30 1:21 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 9:17 [RFC PATCH 0/4] Add support for ARMv8.6 TWED feature Jingyi Wang
2020-09-29 9:17 ` [RFC PATCH 1/4] arm64: cpufeature: TWED support detection Jingyi Wang
2020-09-29 9:17 ` [RFC PATCH 2/4] KVM: arm64: Make use of TWED feature Jingyi Wang
2020-09-29 9:17 ` [RFC PATCH 3/4] KVM: arm64: Use dynamic TWE Delay value Jingyi Wang
2020-09-29 9:17 ` [RFC PATCH 4/4] KVM: arm64: Add trace for TWED update Jingyi Wang
2020-09-29 10:50 ` [RFC PATCH 0/4] Add support for ARMv8.6 TWED feature Marc Zyngier
2020-09-30 1:21 ` Jingyi Wang [this message]
2020-11-13 7:54 ` Jingyi Wang
2020-11-24 3:19 ` Jingyi Wang
2020-11-24 11:02 ` Marc Zyngier
2020-11-26 2:31 ` Jingyi Wang
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=21241889-7fca-5cd3-a5d3-41eb34f9c960@huawei.com \
--to=wangjingyi11@huawei.com \
--cc=catalin.marinas@arm.com \
--cc=fanhenglong@huawei.com \
--cc=kvm@vger.kernel.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=maz@kernel.org \
--cc=prime.zeng@hisilicon.com \
--cc=will@kernel.org \
/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