lkml.org 
[lkml]   [2020]   [Apr]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v5 0/5] Track and expose idle PURR and SPURR ticks
On Mon, Apr 20, 2020 at 03:46:35PM -0700, Tyrel Datwyler wrote:
> On 4/7/20 1:47 AM, Gautham R. Shenoy wrote:
> > From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
> >
> > Hi,
> >
> > This is the fifth version of the patches to track and expose idle PURR
> > and SPURR ticks. These patches are required by tools such as lparstat
> > to compute system utilization for capacity planning purposes.
> >
> > The previous versions can be found here:
> > v4: https://lkml.org/lkml/2020/3/27/323
> > v3: https://lkml.org/lkml/2020/3/11/331
> > v2: https://lkml.org/lkml/2020/2/21/21
> > v1: https://lore.kernel.org/patchwork/cover/1159341/
> >
> > They changes from v4 are:
> >
> > - As suggested by Naveen, moved the functions read_this_idle_purr()
> > and read_this_idle_spurr() from Patch 2 and Patch 3 respectively
> > to Patch 4 where it is invoked.
> >
> > - Dropped Patch 6 which cached the values of purr, spurr,
> > idle_purr, idle_spurr in order to minimize the number of IPIs
> > sent.
> >
> > - Updated the dates for the idle_purr, idle_spurr in the
> > Documentation Patch 5.
> >
> > Motivation:
> > ===========
> > On PSeries LPARs, the data centers planners desire a more accurate
> > view of system utilization per resource such as CPU to plan the system
> > capacity requirements better. Such accuracy can be obtained by reading
> > PURR/SPURR registers for CPU resource utilization.
> >
> > Tools such as lparstat which are used to compute the utilization need
> > to know [S]PURR ticks when the cpu was busy or idle. The [S]PURR
> > counters are already exposed through sysfs. We already account for
> > PURR ticks when we go to idle so that we can update the VPA area. This
> > patchset extends support to account for SPURR ticks when idle, and
> > expose both via per-cpu sysfs files.
> >
> > These patches are required for enhancement to the lparstat utility
> > that compute the CPU utilization based on PURR and SPURR which can be
> > found here :
> > https://groups.google.com/forum/#!topic/powerpc-utils-devel/fYRo69xO9r4
> >
> >
> > With the patches, when lparstat is run on a LPAR running CPU-Hogs,
> > =========================================================================
> > sudo ./src/lparstat -E 1 3
> >
> > System Configuration
> > type=Dedicated mode=Capped smt=8 lcpu=2 mem=4834112 kB cpus=0 ent=2.00
> >
> > ---Actual--- -Normalized-
> > %busy %idle Frequency %busy %idle
> > ------ ------ ------------- ------ ------
> > 1 99.99 0.00 3.35GHz[111%] 110.99 0.00
> > 2 100.00 0.00 3.35GHz[111%] 111.01 0.00
> > 3 100.00 0.00 3.35GHz[111%] 111.00 0.00
> >
> > With patches, when lparstat is run on and idle LPAR
> > =========================================================================
> > System Configuration
> > type=Dedicated mode=Capped smt=8 lcpu=2 mem=4834112 kB cpus=0 ent=2.00
> > ---Actual--- -Normalized-
> > %busy %idle Frequency %busy %idle
> > ------ ------ ------------- ------ ------
> > 1 0.15 99.84 2.17GHz[ 72%] 0.11 71.89
> > 2 0.24 99.76 2.11GHz[ 70%] 0.18 69.82
> > 3 0.24 99.75 2.11GHz[ 70%] 0.18 69.81
> >
> > Gautham R. Shenoy (5):
> > powerpc: Move idle_loop_prolog()/epilog() functions to header file
> > powerpc/idle: Store PURR snapshot in a per-cpu global variable
> > powerpc/pseries: Account for SPURR ticks on idle CPUs
> > powerpc/sysfs: Show idle_purr and idle_spurr for every CPU
> > Documentation: Document sysfs interfaces purr, spurr, idle_purr,
> > idle_spurr
> >
> > Documentation/ABI/testing/sysfs-devices-system-cpu | 39 +++++++++
> > arch/powerpc/include/asm/idle.h | 93 ++++++++++++++++++++++
> > arch/powerpc/kernel/sysfs.c | 82 ++++++++++++++++++-
> > arch/powerpc/platforms/pseries/setup.c | 8 +-
> > drivers/cpuidle/cpuidle-pseries.c | 39 ++-------
> > 5 files changed, 224 insertions(+), 37 deletions(-)
> > create mode 100644 arch/powerpc/include/asm/idle.h
> >
>
> Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>

Thanks for reviewing the patches.

>
> Any chance this is going to be merged in the near future? There is a patchset to
> update lparstat in the powerpc-utils package to calculate PURR/SPURR cpu
> utilization that I would like to merge, but have been holding off to make sure
> we are synced with this proposed patchset.

Michael, could you please consider this for 5.8 ?

--
Thanks and Regards
gautham.

\
 
 \ /
  Last update: 2020-04-23 12:02    [W:0.128 / U:12.088 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site