kvm.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Alexander Graf <graf@amazon.de>
To: Paolo Bonzini <pbonzini@redhat.com>, <milanpa@amazon.com>,
	Milan Pandurov <milanpa@amazon.de>, <kvm@vger.kernel.org>
Cc: <rkrcmar@redhat.com>, <borntraeger@de.ibm.com>
Subject: Re: [PATCH 2/2] kvm: Add ioctl for gathering debug counters
Date: Thu, 23 Jan 2020 15:45:45 +0100	[thread overview]
Message-ID: <c3b61fff-b40e-07f8-03c4-b177fbaab1a3@amazon.de> (raw)
In-Reply-To: <b69546be-a25c-bbea-7e37-c07f019dcf85@redhat.com>



On 23.01.20 15:19, Paolo Bonzini wrote:
> On 23/01/20 13:32, Alexander Graf wrote:
>>> See above: I am not sure they are the same story because their consumers
>>> might be very different from registers.  Registers are generally
>>> consumed by programs (to migrate VMs, for example) and only occasionally
>>> by humans, while stats are meant to be consumed by humans.  We may
>>> disagree on whether this justifies a completely different API...
>>
>> I don't fully agree on the "human" part here.
> 
> I agree it's not entirely about humans, but in general it's going to be
> rules and queries on monitoring tools, where 1) the monitoring tools'
> output is generally not KVM-specific, 2) the rules and queries will be
> written by humans.
> 
> So if the kernel produces insn_emulation_fail, the plugin for the
> monitoring tool will just log kvm.insn_emulation_fail.  If the kernel
> produces 0x10042, the plugin will have to convert it and then log it.
> This is why I'm not sure that providing strings is actually less work
> for userspace.

I think we're in agreement then, just leaning onto the other side of the 
same fence. My take is that if I don't know whether a string is 
necessary, I'd rather not have a string :).

I guess as long as we do get stat information out per-vm as well as 
per-vcpu through vmfd and vcpufd, I'm happy overall.

So how strongly do you feel about the string based approach?


Alex

PS: You could btw easily add a "give me the string for a ONE_REG id" 
interface in KVM to translate from 0x10042 to "insn_emulation_fail" :).



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879



  reply	other threads:[~2020-01-23 14:46 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-15 13:43 [PATCH 2/2] kvm: Add ioctl for gathering debug counters Milan Pandurov
2020-01-15 14:04 ` Alexander Graf
2020-01-15 14:43   ` milanpa
2020-01-15 14:59     ` Alexander Graf
2020-01-17 23:38       ` Paolo Bonzini
2020-01-20 17:53         ` Alexander Graf
2020-01-20 18:57           ` milanpa
2020-01-21 15:38             ` Alexander Graf
2020-01-23 12:08               ` Paolo Bonzini
2020-01-23 12:32                 ` Alexander Graf
2020-01-23 14:19                   ` Paolo Bonzini
2020-01-23 14:45                     ` Alexander Graf [this message]
2020-01-23 14:50                       ` Paolo Bonzini
2020-01-23 14:58                         ` Alexander Graf
2020-01-23 15:05                           ` Paolo Bonzini
2020-01-23 15:27                             ` milanpa
2020-01-23 16:15                               ` Paolo Bonzini
2020-01-23 18:31                                 ` milanpa

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=c3b61fff-b40e-07f8-03c4-b177fbaab1a3@amazon.de \
    --to=graf@amazon.de \
    --cc=borntraeger@de.ibm.com \
    --cc=kvm@vger.kernel.org \
    --cc=milanpa@amazon.com \
    --cc=milanpa@amazon.de \
    --cc=pbonzini@redhat.com \
    --cc=rkrcmar@redhat.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;
as well as URLs for NNTP newsgroup(s).