From: Peter Xu <peterx@redhat.com>
To: Ben Gardon <bgardon@google.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Peter Shier <pshier@google.com>,
Junaid Shahid <junaids@google.com>,
Jim Mattson <jmattson@google.com>,
Makarand Sonare <makarandsonare@google.com>,
Kai Huang <kai.huang@intel.com>
Subject: Re: [PATCH] KVM: VMX: Optimize flushing the PML buffer
Date: Thu, 4 Feb 2021 17:51:44 -0500 [thread overview]
Message-ID: <20210204225144.GU6468@xz-x1> (raw)
In-Reply-To: <20210204221959.232582-1-bgardon@google.com>
Hi, Ben,
On Thu, Feb 04, 2021 at 02:19:59PM -0800, Ben Gardon wrote:
> The average time for each run demonstrated a strange bimodal distribution,
> with clusters around 2 seconds and 2.5 seconds. This may have been a
> result of vCPU migration between NUMA nodes.
Have you thought about using numactl or similar technique to verify your idea
(force both vcpu threads binding, and memory allocations)?
From the numbers it already shows improvements indeed, but just curious since
you raised this up. :)
> @@ -5707,13 +5708,18 @@ static void vmx_flush_pml_buffer(struct kvm_vcpu *vcpu)
> else
> pml_idx++;
>
> + memslots = kvm_vcpu_memslots(vcpu);
> +
> pml_buf = page_address(vmx->pml_pg);
> for (; pml_idx < PML_ENTITY_NUM; pml_idx++) {
> + struct kvm_memory_slot *memslot;
> u64 gpa;
>
> gpa = pml_buf[pml_idx];
> WARN_ON(gpa & (PAGE_SIZE - 1));
> - kvm_vcpu_mark_page_dirty(vcpu, gpa >> PAGE_SHIFT);
> +
> + memslot = __gfn_to_memslot(memslots, gpa >> PAGE_SHIFT);
> + mark_page_dirty_in_slot(vcpu->kvm, memslot, gpa >> PAGE_SHIFT);
Since at it: make "gpa >> PAGE_SHIFT" a temp var too?
Thanks,
--
Peter Xu
next prev parent reply other threads:[~2021-02-04 22:53 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-04 22:19 [PATCH] KVM: VMX: Optimize flushing the PML buffer Ben Gardon
2021-02-04 22:51 ` Peter Xu [this message]
2021-02-05 0:02 ` Ben Gardon
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=20210204225144.GU6468@xz-x1 \
--to=peterx@redhat.com \
--cc=bgardon@google.com \
--cc=jmattson@google.com \
--cc=junaids@google.com \
--cc=kai.huang@intel.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=makarandsonare@google.com \
--cc=pbonzini@redhat.com \
--cc=pshier@google.com \
--cc=seanjc@google.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