linux-kernel - [PATCH RESEND v4 0/4] cpufreq: powernv: Redesign the presentation of throttle notification

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1452594267-12844-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com>
Date:	Tue, 12 Jan 2016 04:24:23 -0600
From:	Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com>
To:	linuxppc-dev@...abs.org, linux-kernel@...r.kernel.org
Cc:	rjw@...ysocki.net, viresh.kumar@...aro.org,
	linux-pm@...r.kernel.org, pc@...ibm.com, anton@...ba.org,
	ego@...ux.vnet.ibm.com, shreyas@...ux.vnet.ibm.com,
	Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com>
Subject: [PATCH RESEND v4 0/4] cpufreq: powernv: Redesign the presentation of throttle notification

In POWER8, OCC(On-Chip-Controller) can throttle the frequency of the
CPU when the chip crosses its thermal and power limits. Currently,
powernv-cpufreq driver detects and reports this event as a console
message. Some machines may not sustain the max turbo frequency in all
conditions and can be throttled frequently. This can lead to the
flooding of console with throttle messages. So this patchset aims to
redesign the presentation of this event via sysfs counters and
tracepoints. 

Patches [2] to [4] will add a perf trace point "power:powernv_throttle" and
sysfs throttle counter stats in /sys/devices/system/cpu/cpufreq/chipN.
Patch [1] solves a bug in powernv_cpufreq_throttle_check(), which calls in to
cpu_to_chip_id() in hot path which reads DT every time to find the chip id.

Resending the patchset as I has cc'ed stable@...r.kernel.org in developemnt
cycle and used --in-reply-to to post a new version.

Changes from v3:
- Add a fix to replace cpu_to_chip_id() with simpler PIR shift to obtain the
  chip id.
- Break patch2 in to two patches separating the tracepoint and sysfs attribute
  changes.

Changes from v2:
- Fixed kbuild test warning.
drivers/cpufreq/powernv-cpufreq.c:609:2: warning: ignoring return
value of 'kstrtoint', declared with attribute warn_unused_result
[-Wunused-result]

Shilpasri G Bhat (4):
  cpufreq: powernv: Remove cpu_to_chip_id() from hot-path
  cpufreq: powernv/tracing: Add powernv_throttle tracepoint
  cpufreq: powernv: Add a trace print for the throttle event
  cpufreq: powernv: Add sysfs attributes to show throttle stats

 drivers/cpufreq/powernv-cpufreq.c | 279 +++++++++++++++++++++++++++++++-------
 include/trace/events/power.h      |  22 +++
 kernel/trace/power-traces.c       |   1 +
 3 files changed, 250 insertions(+), 52 deletions(-)

-- 
1.9.1