From: Marc Zyngier <maz@kernel.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Aaron Lewis <aaronlewis@google.com>, KVM <kvm@vger.kernel.org>,
Venkatesh Srinivas <venkateshs@google.com>,
Peter Shier <pshier@google.com>, Ben Gardon <bgardon@google.com>,
David Matlack <dmatlack@google.com>,
Will Deacon <will@kernel.org>,
KVMARM <kvmarm@lists.cs.columbia.edu>,
Jim Mattson <jmattson@google.com>
Subject: Re: [PATCH v1 3/3] KVM: arm64: Add histogram stats for handling time of arch specific exit reasons
Date: Thu, 23 Sep 2021 08:45:22 +0100 [thread overview]
Message-ID: <8735pvvip9.wl-maz@kernel.org> (raw)
In-Reply-To: <a1e77794-de94-1fb7-c7d3-a80c34f770a4@redhat.com>
On Thu, 23 Sep 2021 07:36:21 +0100,
Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 22/09/21 20:53, Marc Zyngier wrote:
> > I definitely regret adding the current KVM trace points, as they
> > don't show what I need, and I can't change them as they are ABI.
>
> I disagree that they are ABI. And even if you don't want to change
> them, you can always add parameters or remove them.
We'll have to agree to disagree here. Experience has told me that
anything that gets exposed to userspace has to stay forever. There are
countless examples of that on the arm64 side (cue the bogomips debate,
the recent /proc/interrupts repainting).
We had that discussion a few KSs ago (triggered by this[1] if I
remember correctly), and I don't think anything has changed since.
As for removing them, that would probably be best for some (if not
most) of them.
M.
[1] https://lwn.net/Articles/737532/
--
Without deviation from the norm, progress is not possible.
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next prev parent reply other threads:[~2021-09-23 7:45 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-22 1:08 [PATCH v1 1/3] KVM: arm64: Add arch specific exit reasons Jing Zhang
2021-09-22 1:08 ` [PATCH v1 2/3] KVM: arm64: Add counter stats for " Jing Zhang
2021-09-22 1:08 ` [PATCH v1 3/3] KVM: arm64: Add histogram stats for handling time of " Jing Zhang
2021-09-22 11:22 ` Marc Zyngier
2021-09-22 15:37 ` Paolo Bonzini
2021-09-22 16:09 ` Jing Zhang
2021-09-22 18:13 ` Sean Christopherson
2021-09-22 18:53 ` Marc Zyngier
2021-09-22 23:22 ` David Matlack
2021-09-30 14:04 ` Marc Zyngier
2021-09-30 18:05 ` Sean Christopherson
2021-09-23 6:36 ` Paolo Bonzini
2021-09-23 7:45 ` Marc Zyngier [this message]
2021-09-23 9:44 ` Paolo Bonzini
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