From: Mark Rutland <mark.rutland@arm.com>
To: Shawn Guo <shawnguo@kernel.org>
Cc: Zhi Li <lznuaa@gmail.com>, Zhengyu Shen <zhengyu.shen@nxp.com>,
Frank Li <frank.li@nxp.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
kernel list <linux-kernel@vger.kernel.org>,
peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
alexander.shishkin@linux.intel.com
Subject: Re: [PATCH v3] Added perf functionality to mmdc driver
Date: Tue, 30 Aug 2016 13:54:20 +0100 [thread overview]
Message-ID: <20160830125420.GG1223@leverpostej> (raw)
In-Reply-To: <20160830114329.GB8366@tiger>
Hi,
On Tue, Aug 30, 2016 at 07:43:29PM +0800, Shawn Guo wrote:
> On Mon, Aug 29, 2016 at 11:06:44AM -0500, Zhi Li wrote:
> > On Wed, Aug 17, 2016 at 2:42 PM, Zhengyu Shen <zhengyu.shen@nxp.com> wrote:
> > > MMDC is a multi-mode DDR controller that supports DDR3/DDR3L x16/x32/x64
> > > and LPDDR2 two channel x16/x32 memory types. MMDC is configurable, high
> > > performance, and optimized. MMDC is present on i.MX6 Quad and i.MX6
> > > QuadPlus devices, but this driver only supports i.MX6 Quad at the moment.
> > > MMDC provides registers for performance counters which read via this
> > > driver to help debug memory throughput and similar issues.
> > >
> > > $ perf stat -a -e mmdc/busy-cycles/,mmdc/read-accesses/,mmdc/read-bytes/,mmdc/total-cycles/,mmdc/write-accesses/,mmdc/write-bytes/ dd if=/dev/zero of=/dev/null bs=1M count=5000
> > > Performance counter stats for 'dd if=/dev/zero of=/dev/null bs=1M count=5000':
> > >
> > > 898021787 mmdc/busy-cycles/
> > > 14819600 mmdc/read-accesses/
> > > 471.30 MB mmdc/read-bytes/
> > > 2815419216 mmdc/total-cycles/
> > > 13367354 mmdc/write-accesses/
> > > 427.76 MB mmdc/write-bytes/
> > >
> > > 5.334757334 seconds time elapsed
> > >
> > > Signed-off-by: Zhengyu Shen <zhengyu.shen@nxp.com>
> > > Signed-off-by: Frank Li <frank.li@nxp.com>
> >
> > Shawn Guo:
> >
> > No new comments got more than 1 weeks.
> > Did you plan accept it?
>
> @Mark, how do you think of this version?
Sorry, I've been away for the last week and haven't had the chance to
look at this yet. I will try to get round to it in the next few days.
In the meantime, could you please try attacking this with Vince's perf
fuzzer [1] (as root, or with perf_event_paranoid dropped to -1)? It's
rather good at finding (subtle) issues in drivers.
Thanks,
Mark.
[1] https://github.com/deater/perf_event_tests
next prev parent reply other threads:[~2016-08-30 12:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-17 19:42 [PATCH v3] Added perf functionality to mmdc driver Zhengyu Shen
2016-08-29 16:06 ` Zhi Li
2016-08-30 11:43 ` Shawn Guo
2016-08-30 12:54 ` Mark Rutland [this message]
2016-08-30 20:01 ` Zhengyu Shen
2016-08-31 10:30 ` Mark Rutland
2016-08-31 13:46 ` Zhengyu Shen
2016-08-30 14:06 ` Shawn Guo
2016-08-31 13:08 ` Suzuki K Poulose
2016-08-31 16:20 ` Suzuki K Poulose
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=20160830125420.GG1223@leverpostej \
--to=mark.rutland@arm.com \
--cc=acme@kernel.org \
--cc=alexander.shishkin@linux.intel.com \
--cc=frank.li@nxp.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lznuaa@gmail.com \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=shawnguo@kernel.org \
--cc=zhengyu.shen@nxp.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).