Thread (23 messages) 23 messages, 4 authors, 2018-08-21

[PATCH v3 0/7] perf: Add ioctl for PMU driver configuration

From: mathieu.poirier@linaro.org (Mathieu Poirier)
Date: 2018-08-14 16:16:13
Also in: lkml

On Mon, 13 Aug 2018 at 11:46, Kim Phillips [off-list ref] wrote:
On Wed, 18 Jul 2018 15:48:00 -0600
Mathieu Poirier [off-list ref] wrote:
quoted
This set adds the capability to communiate event specific configuration
to the PMU kernel driver using an ioctl().  The functionatlity is made
generic enough for anyone to use but is targeted at the identification
of CoreSight sinks when operating in CPU-wide trace scenarios.

---
Changes for V3:
. Return an error for CPU-wide scenarios while the feature is being
  implemented (Kim)
Hi, I'm giving this series a short test-drive on Juno.
Hi,
It yields success for the --per-thread case..:

$ sudo taskset -c 0 ./perf record -e cs_etm/@20010000.etf/ --per-thread uname -a
Linux juno 4.18.0-rc8-00011-gb82af52c4b35-dirty #147 SMP PREEMPT Thu Aug 9 11:20:37 CDT 2018 aarch64 GNU/Linux
[ perf record: Woken up 0 times to write data ]
Warning:
AUX data lost 1 times out of 2!

[ perf record: Captured and wrote 0.067 MB perf.data ]
$

..but not for CPU-wide?:

$ sudo taskset -c 0 ./perf record -e cs_etm/@20010000.etf/ uname -a
failed to mmap with 12 (Cannot allocate memory)
$ sudo taskset -c 0 ./perf record -e cs_etm/@20010000.etf/ -C 0 uname -a
failed to mmap with 12 (Cannot allocate memory)
$
This patchset is getting very old and a fair amount of things have
changed since then.  I'm hoping to be coming out with a new one
shortly.  Nonetheless the above is returning an error in CPU-wide
scenarios while the feature is being implemented.  Isn't what you
requested or have I misunderstood your comment?
Thanks,

Kim
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