kvm.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Xu, Like" <like.xu@intel.com>
To: Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: Stephane Eranian <eranian@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Like Xu <like.xu@linux.intel.com>
Subject: Re: [PATCH] KVM: x86/pmu: Fix HW_REF_CPU_CYCLES event pseudo-encoding in intel_arch_events[]
Date: Mon, 18 Jan 2021 12:40:39 +0800	[thread overview]
Message-ID: <b3623ea4-b2a1-e825-68f9-d97a6e7a07f4@intel.com> (raw)
In-Reply-To: <YAHRMK5SmrmMx8hg@google.com>

On 2021/1/16 1:30, Sean Christopherson wrote:
> On Fri, Jan 15, 2021, Like Xu wrote:
>> Ping ?
>>
>> On 2020/12/30 16:19, Like Xu wrote:
>>> The HW_REF_CPU_CYCLES event on the fixed counter 2 is pseudo-encoded as
>>> 0x0300 in the intel_perfmon_event_map[]. Correct its usage.
>>>
>>> Fixes: 62079d8a4312 ("KVM: PMU: add proper support for fixed counter 2")
>>> Signed-off-by: Like Xu <like.xu@linux.intel.com>
> Reviewed-by: Sean Christopherson <seanjc@google.com>
thx.
>
>>> ---
>>>    arch/x86/kvm/vmx/pmu_intel.c | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
>>> index a886a47daebd..013e8d253dfa 100644
>>> --- a/arch/x86/kvm/vmx/pmu_intel.c
>>> +++ b/arch/x86/kvm/vmx/pmu_intel.c
>>> @@ -29,7 +29,7 @@ static struct kvm_event_hw_type_mapping intel_arch_events[] = {
>>>    	[4] = { 0x2e, 0x41, PERF_COUNT_HW_CACHE_MISSES },
>>>    	[5] = { 0xc4, 0x00, PERF_COUNT_HW_BRANCH_INSTRUCTIONS },
>>>    	[6] = { 0xc5, 0x00, PERF_COUNT_HW_BRANCH_MISSES },
>>> -	[7] = { 0x00, 0x30, PERF_COUNT_HW_REF_CPU_CYCLES },
>>> +	[7] = { 0x00, 0x03, PERF_COUNT_HW_REF_CPU_CYCLES },
> In a follow up patch, would it be sane/appropriate to define these magic numbers
> in asm/perf_event.h and share them between intel_perfmon_event_map and
> intel_arch_events?  Without this patch, it's not at all obvious that these are
> intended to align with the Core (arch?) event definitions.

The asm/perf_event.h is x86 generic and svm has a amd_perfmon_event_map.

How about adding an interface similar to perf_get_x86_pmu_capability()
so that we can use magic numbers directly from the host perf ?
(it looks we may have a performance drop, compared to static array)

---
thx, likexu

>
>>>    };
>>>    /* mapping between fixed pmc index and intel_arch_events array */


  reply	other threads:[~2021-01-18  4:41 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-30  8:19 Like Xu
2021-01-15  8:46 ` Like Xu
2021-01-15 17:30   ` Sean Christopherson
2021-01-18  4:40     ` Xu, Like [this message]
2021-01-20  1:13       ` Sean Christopherson
2021-01-18 17:57 ` Paolo Bonzini

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=b3623ea4-b2a1-e825-68f9-d97a6e7a07f4@intel.com \
    --to=like.xu@intel.com \
    --cc=eranian@google.com \
    --cc=jmattson@google.com \
    --cc=joro@8bytes.org \
    --cc=kvm@vger.kernel.org \
    --cc=like.xu@linux.intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pbonzini@redhat.com \
    --cc=seanjc@google.com \
    --cc=vkuznets@redhat.com \
    --cc=wanpengli@tencent.com \
    --subject='Re: [PATCH] KVM: x86/pmu: Fix HW_REF_CPU_CYCLES event pseudo-encoding in intel_arch_events[]' \
    /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

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).