linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: <joro@8bytes.org>, <bp@alien8.de>, <mingo@redhat.com>,
	<acme@kernel.org>, <andihartmann@freenet.de>,
	<linux-kernel@vger.kernel.org>,
	<iommu@lists.linux-foundation.org>
Subject: Re: [PATCH V4 5/6] perf/amd/iommu: Enable support for multiple IOMMUs
Date: Tue, 23 Feb 2016 12:12:42 +0700	[thread overview]
Message-ID: <56CBEA4A.8070001@amd.com> (raw)
In-Reply-To: <20160222140741.GH6357@twins.programming.kicks-ass.net>

Hi

On 02/22/2016 09:07 PM, Peter Zijlstra wrote:
> On Mon, Feb 22, 2016 at 03:00:31PM +0700, Suravee Suthikulpanit wrote:
>>> So I really don't have time to review new muck while I'm hunting perf
>>> core fail, but Boris made me look at this.
>>>
>>> This is crazy, if you have multiple IOMMUs then create an event per
>>> IOMMU, do _NOT_ fold them all into a single event.
>>
>> These are system-wide events, which are programmed on every IOMMU the same
>> way. I am not sure what you meant by creating an event per IOMMU. Do you
>> mean I should create internal per-IOMMU struct perf_event for each event?
>
> No, I meant to expose each IOMMU individually to userspace, as a
> separate device.
>
> Is there never a case to profile just one of the IOMMUs ?
>

I see. That's definitely doable and simpler to implement.

I was not sure if making users specify the IOMMU instance (e.g. 
amd_iommu_0/<ev name> , amd_iommu_1/<ev_name>, ....) would be too 
tedious. However, this would actually give users better control of the 
performance events, which is a good trade-off. I think it is acceptable.

I'll make the change and send this out in V5.

Thanks,
Suravee

  reply	other threads:[~2016-02-23  5:13 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-11  9:15 [PATCH V4 0/6] perf/amd/iommu: Enable multi-IOMMU support Suravee Suthikulpanit
2016-02-11  9:15 ` [PATCH V4 1/6] perf/amd/iommu: Consolidate and move perf_event_amd_iommu header Suravee Suthikulpanit
2016-02-11  9:15 ` [PATCH V4 2/6] perf/amd/iommu: Modify functions to query max banks and counters Suravee Suthikulpanit
2016-02-18 11:11   ` Borislav Petkov
2016-02-22  4:55     ` Suravee Suthikulpanit
2016-02-11  9:15 ` [PATCH V4 3/6] iommu/amd: Introduce amd_iommu_get_num_iommus() Suravee Suthikulpanit
2016-02-11  9:15 ` [PATCH V4 4/6] perf/amd/iommu: Introduce get_iommu_bnk_cnt_evt_idx Suravee Suthikulpanit
2016-02-18 11:45   ` Borislav Petkov
2016-02-11  9:15 ` [PATCH V4 5/6] perf/amd/iommu: Enable support for multiple IOMMUs Suravee Suthikulpanit
2016-02-18 13:18   ` Peter Zijlstra
2016-02-22  8:00     ` Suravee Suthikulpanit
2016-02-22 14:07       ` Peter Zijlstra
2016-02-23  5:12         ` Suravee Suthikulpanit [this message]
2016-02-23  5:24           ` Alex Williamson
2016-02-23  9:56             ` Suravee Suthikulpanit
2016-02-18 13:21   ` Borislav Petkov
2016-02-11  9:15 ` [PATCH V4 6/6] perf/amd/iommu: Clean up print messages pr_debug Suravee Suthikulpanit
2016-02-18 13:22   ` Borislav Petkov
2016-02-18  2:30 ` [PATCH V4 0/6] perf/amd/iommu: Enable multi-IOMMU support Suravee Suthikulpanit
2016-02-23 11:04 ` Joerg Roedel
2016-02-23 11:27   ` Suravee Suthikulpanit
2016-02-23 11:39     ` Suravee Suthikulpanit
2016-02-23 12:12       ` [PATCH] iommu/amd: Fix boot warning when device 00:00.0 is not iommu Joerg Roedel

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=56CBEA4A.8070001@amd.com \
    --to=suravee.suthikulpanit@amd.com \
    --cc=acme@kernel.org \
    --cc=andihartmann@freenet.de \
    --cc=bp@alien8.de \
    --cc=iommu@lists.linux-foundation.org \
    --cc=joro@8bytes.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@redhat.com \
    --cc=peterz@infradead.org \
    /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).