From: Zhengyu Shen <zhengyu.shen@nxp.com>
To: Mark Rutland <mark.rutland@arm.com>, Shawn Guo <shawnguo@kernel.org>
Cc: Zhi Li <lznuaa@gmail.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" <peterz@infradead.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"acme@kernel.org" <acme@kernel.org>,
"alexander.shishkin@linux.intel.com"
<alexander.shishkin@linux.intel.com>
Subject: RE: [PATCH v3] Added perf functionality to mmdc driver
Date: Tue, 30 Aug 2016 20:01:18 +0000 [thread overview]
Message-ID: <DB5PR04MB1430D8A0284123B5C475800E9FE00@DB5PR04MB1430.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20160830125420.GG1223@leverpostej>
> 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
Hi, I've done some testing with the fuzzer. Mmdc was only responsible
for one crash which I fixed (had to remove the event from the pmu properly).
Other drivers also cause crashes and the program reports that events are
Throttling. Is this normal?
next prev parent reply other threads:[~2016-08-30 20:01 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
2016-08-30 20:01 ` Zhengyu Shen [this message]
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
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