Re: [PATCH 00/30] PREEMPT_AUTO: support lazy rescheduling

From: Raghavendra K T
Date: Wed Feb 21 2024 - 23:06:27 EST


On 2/22/2024 2:46 AM, Ankur Arora wrote:

Raghavendra K T <raghavendra.kt@xxxxxxx> writes:

On 2/21/2024 10:45 PM, Thomas Gleixner wrote:
On Wed, Feb 21 2024 at 17:53, Raghavendra K T wrote:
Configuration tested.
a) Base kernel (6.7),
Which scheduling model is the baseline using?


baseline is also PREEMPT_DYNAMIC with voluntary preemption

b) patched with PREEMPT_AUTO voluntary preemption.
c) patched with PREEMPT_DYNAMIC voluntary preemption.

Workloads I tested and their %gain,
case b case c
NAS +2.7 +1.9
Hashjoin, +0 +0
XSBench +1.7 +0
Graph500, -6 +0
The Graph500 stands out. Needs some analysis.


Sure. Will do more detailed analysis and comeback on this.

Thanks Raghu. Please keep me posted.

Also, let me try to reproduce this locally. Could you post the
parameters that you used for the Graph500 run?


This was run as part of test suite where by from output, Parameters, I see as :

SCALE: 27
nvtx: 134217728
edgefactor: 16
terasize: 3.43597383679999993e-02
A: 5.69999999999999951e-01
B: 1.90000000000000002e-01
C: 1.90000000000000002e-01
D: 5.00000000000000444e-02
generation_time: 4.93902114900000022e+00
construction_time: 2.55216929010000015e+01
nbfs: 64

Meanwhile since stddev for the runs I saw was little bit on higher side,
I did think results are Okay.

Rerunning with more iterations to see if there is a valid concern, if so I will dig more deep as Thomas pointed.
Also will post the results of run.

Thanks and Regards
- Raghu