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From: shrikanth suresh hegde <sshegde@linux.vnet.ibm.com>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
	dietmar.eggemann@arm.com, rostedt@goodmis.org,
	bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
	vschneid@redhat.com, linux-kernel@vger.kernel.org,
	parth@linux.ibm.com, qais.yousef@arm.com, chris.hyser@oracle.com,
	patrick.bellasi@matbug.net, David.Laight@aculab.com,
	pjt@google.com, pavel@ucw.cz, tj@kernel.org, qperret@google.com,
	tim.c.chen@linux.intel.com, joshdon@google.com, timj@gnu.org,
	kprateek.nayak@amd.com, yu.c.chen@intel.com,
	youssefesmat@chromium.org, joel@joelfernandes.org
Subject: Re: [PATCH v7 0/9] Add latency priority for CFS class
Date: Sun, 13 Nov 2022 14:04:51 +0530	[thread overview]
Message-ID: <78d06985-c31a-cdbf-08ef-5b4772a81a03@linux.vnet.ibm.com> (raw)
In-Reply-To: <20221028093403.6673-1-vincent.guittot@linaro.org>


> This patchset restarts the work about adding a latency priority to describe
> the latency tolerance of cfs tasks.

Hi Vincent.
  
Tested the patches on the power10 machine. It is 80 core system with SMT=8. i.e
total of 640 cpus. on the large workload which mainly interacts with the
database there is minor improvement of 3-5%.

the method followed is creating a cgroup, assigning a latency nice value of -20,
-10, 0 and adding the tasks to procs of the cgroup. outside of cgroup, stress-ng
load is running and it is not set any latency value. stress-ng --cpu=768 -l 50

with microbenchmarks, hackbench the values are more or less the same. for large
process pool of 60, there is 10% improvement. schbench tail latencies show
significant improvement with low and medium load upto 256 groups. only 512
groups shows a slight decline.

Hackbench (Iterations or N=50)
Process             6.1_Base        6.1_Latency_Nice
10                      0.13            0.14
20                      0.18            0.18
30                      0.24            0.25
40                      0.34            0.33
50                      0.40            0.41
60                      0.53            0.49

schbench (Iterations or N=5)

Groups: 1
                     6.1_Base        6.1_Latency_Nice
50.0th:                 10.8             9.8
75.0th:                 12.4            11.4
90.0th:                 14.2            13.2
95.0th:                 15.6            14.6
99.0th:                 27.8            19.0
99.5th:                 38.0            21.6
99.9th:                 66.2            25.4

Groups: 2
                     6.1_Base        6.1_Latency_Nice
50.0th:                 11.2            10.8
75.0th:                 13.2            12.4
90.0th:                 15.0            15.0
95.0th:                 16.6            16.6
99.0th:                 22.4            22.8
99.5th:                 23.8            27.8
99.9th:                 30.2            45.6

Groups: 4
                     6.1_Base        6.1_Latency_Nice
50.0th:                 13.8            11.2
75.0th:                 16.0            13.2
90.0th:                 18.6            15.2
95.0th:                 20.4            16.6
99.0th:                 28.8            21.6
99.5th:                 48.8            25.2
99.9th:                900.2            47.0

Groups: 8
                     6.1_Base        6.1_Latency_Nice
50.0th:                 17.8            14.4
75.0th:                 21.8            17.2
90.0th:                 25.4            20.4
95.0th:                 28.0            22.4
99.0th:                 52.8            28.4
99.5th:                156.4            32.6
99.9th:               1990.2            52.0

Groups: 16
                     6.1_Base        6.1_Latency_Nice
50.0th:                 26.0            21.0
75.0th:                 33.0            27.8
90.0th:                 39.6            34.4
95.0th:                 43.4            38.6
99.0th:                 66.8            48.8
99.5th:                170.6            60.6
99.9th:               3308.8           201.6

Groups: 32
                     6.1_Base        6.1_Latency_Nice
50.0th:                 40.8            38.6
75.0th:                 55.4            52.8
90.0th:                 67.0            64.2
95.0th:                 74.2            71.6
99.0th:                106.0            90.0
99.5th:                323.8           133.0
99.9th:               4789.6           459.2

Groups: 64
                     6.1_Base        6.1_Latency_Nice
50.0th:                 72.6            68.2
75.0th:                103.4            97.8
90.0th:                127.6           120.0
95.0th:                141.2           132.0
99.0th:                343.4           158.4
99.5th:               1609.0           180.8
99.9th:               6571.2           686.6

Groups: 128
                     6.1_Base        6.1_Latency_Nice
50.0th:                147.2           147.2
75.0th:                216.4           217.2
90.0th:                268.4           268.2
95.0th:                300.6           294.8
99.0th:               3500.0           638.6
99.5th:               5995.2          2522.8
99.9th:              10390.4          9451.2

Groups: 256
                     6.1_Base        6.1_Latency_Nice
50.0th:                340.8           333.2
75.0th:                551.8           530.2
90.0th:               3528.4          1919.2
95.0th:               7312.8          5558.4
99.0th:              14630.4         12912.0
99.5th:              17955.2         14950.4
99.9th:              23059.2         20230.4

Groups: 512
                     6.1_Base        6.1_Latency_Nice
50.0th:               1021.8           990.6
75.0th:               9545.6         10044.8
90.0th:              20972.8         21638.4
95.0th:              29971.2         30291.2
99.0th:              42355.2         46707.2
99.5th:              48550.4         52057.6
99.9th:              58867.2         60147.2

Tested-by: shrikanth Hegde <sshegde@linux.vnet.ibm.com>


  parent reply	other threads:[~2022-11-13  8:51 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-28  9:33 Vincent Guittot
2022-10-28  9:33 ` [PATCH v7 1/9] sched/fair: fix unfairness at wakeup Vincent Guittot
2022-11-05 14:32   ` Chen Yu
2022-11-07  8:00     ` Vincent Guittot
2022-10-28  9:33 ` [PATCH v7 2/9] sched: Introduce latency-nice as a per-task attribute Vincent Guittot
2022-10-28  9:33 ` [PATCH v7 3/9] sched/core: Propagate parent task's latency requirements to the child task Vincent Guittot
2022-10-28  9:33 ` [PATCH v7 4/9] sched: Allow sched_{get,set}attr to change latency_nice of the task Vincent Guittot
2022-10-28  9:33 ` [PATCH v7 5/9] sched/fair: Take into account latency priority at wakeup Vincent Guittot
2022-11-13  8:02   ` shrikanth suresh hegde
2022-11-13  8:39   ` shrikanth suresh hegde
2022-11-14 10:36     ` Vincent Guittot
2022-10-28  9:34 ` [PATCH v7 6/9] sched/fair: Add sched group latency support Vincent Guittot
2022-11-01 19:28   ` Qais Yousef
2022-11-03  8:46     ` Vincent Guittot
2022-11-03 14:27       ` Qais Yousef
2022-11-03 17:02         ` Vincent Guittot
2022-11-04 10:14           ` Joel Fernandes
2022-11-04 10:37             ` Vincent Guittot
2022-11-04 10:48               ` Joel Fernandes
2022-11-04 10:57                 ` Vincent Guittot
2022-11-04 10:55               ` Joel Fernandes
2022-11-04 12:06                 ` Qais Yousef
2022-11-04 11:47             ` Qais Yousef
2022-11-04 11:21           ` Qais Yousef
2022-11-04 13:13             ` Joel Fernandes
2022-11-05 14:28               ` Qais Yousef
2022-11-04 14:24             ` Vincent Guittot
2022-11-04 14:57               ` Joel Fernandes
2022-11-04 15:03                 ` Vincent Guittot
2022-11-04 15:12                   ` Joel Fernandes
2022-11-04 15:23                     ` Vincent Guittot
2022-11-05 13:41                 ` Qais Yousef
2022-10-28  9:34 ` [PATCH v7 7/9] sched/core: Support latency priority with sched core Vincent Guittot
2022-10-28  9:34 ` [PATCH v7 8/9] sched/fair: Add latency list Vincent Guittot
2022-10-28  9:34 ` [PATCH v7 9/9] sched/fair: remove check_preempt_from_others Vincent Guittot
2022-11-13  7:56 ` [PATCH v7 0/9] Add latency priority for CFS class shrikanth suresh hegde
2022-11-13  8:34 ` shrikanth suresh hegde [this message]
2022-11-14 10:40   ` Vincent Guittot

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