From: Mikulas Patocka <mpatocka@redhat.com>
To: Haozhong Zhang <haozhong.zhang@intel.com>
Cc: kvm@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
rkrcmar@redhat.com, Xiao Guangrong <xiaoguangrong.eric@gmail.com>,
Dan Williams <dan.j.williams@intel.com>,
ivan.d.cuevas.escareno@intel.com, karthik.kumar@intel.com,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Borislav Petkov <bp@suse.de>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [PATCH v2 0/2] KVM: MMU: fix kvm_is_mmio_pfn()
Date: Wed, 8 Nov 2017 07:24:29 -0500 (EST) [thread overview]
Message-ID: <alpine.LRH.2.02.1711080723430.12294@file01.intranet.prod.int.rdu2.redhat.com> (raw)
In-Reply-To: <20171108013032.n5xyjt75bgy2g73w@hz-desktop>
On Wed, 8 Nov 2017, Haozhong Zhang wrote:
> On 11/03/17 10:15 -0400, Mikulas Patocka wrote:
> >
> >
> > On Tue, 31 Oct 2017, Haozhong Zhang wrote:
> >
> > > [I just copy the commit message from patch 2]
> > >
> > > Some reserved pages, such as those from NVDIMM DAX devices, are
> > > not for MMIO, and can be mapped with cached memory type for better
> > > performance. However, the above check misconceives those pages as
> >
> > Note that cached memory type on persistent memory has horrible
> > performance. The clwb instruction on Broadwell is very slow - when you
> > write to persistent memory and use clwb to flush cache, the performance is
> > about 350MB/s.
>
> Wasn't clwb first introduced on Skylake?
>
> Haozhong
You're right - the clwb() function uses clflushopt on Broadwell - that's
what I meant is slow.
Mikulas
prev parent reply other threads:[~2017-11-08 12:24 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-31 11:48 [PATCH v2 0/2] KVM: MMU: fix kvm_is_mmio_pfn() Haozhong Zhang
2017-10-31 11:48 ` [PATCH v2 1/2] x86/mm: expose lookup_memtype() Haozhong Zhang
2017-10-31 11:48 ` [PATCH v2 2/2] KVM: MMU: consider host cache mode in MMIO page check Haozhong Zhang
2017-11-02 7:56 ` Xiao Guangrong
2017-11-02 9:20 ` Haozhong Zhang
2017-11-02 6:48 ` [PATCH v2 0/2] KVM: MMU: fix kvm_is_mmio_pfn() Haozhong Zhang
2017-11-02 17:37 ` Konrad Rzeszutek Wilk
2017-11-03 0:26 ` Haozhong Zhang
2017-11-03 14:15 ` Mikulas Patocka
2017-11-08 1:30 ` Haozhong Zhang
2017-11-08 12:24 ` Mikulas Patocka [this message]
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