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Message-ID: <af122806-8325-4302-991f-9c0dc1857bfe@amd.com>
Date: Thu, 22 Feb 2024 18:34:33 +0530
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH 00/30] PREEMPT_AUTO: support lazy rescheduling
Content-Language: en-US
To: Thomas Gleixner <tglx@linutronix.de>,
 Ankur Arora <ankur.a.arora@oracle.com>, linux-kernel@vger.kernel.org
Cc: peterz@infradead.org, torvalds@linux-foundation.org, paulmck@kernel.org,
 akpm@linux-foundation.org, luto@kernel.org, bp@alien8.de,
 dave.hansen@linux.intel.com, hpa@zytor.com, mingo@redhat.com,
 juri.lelli@redhat.com, vincent.guittot@linaro.org, willy@infradead.org,
 mgorman@suse.de, jpoimboe@kernel.org, mark.rutland@arm.com, jgross@suse.com,
 andrew.cooper3@citrix.com, bristot@kernel.org,
 mathieu.desnoyers@efficios.com, geert@linux-m68k.org,
 glaubitz@physik.fu-berlin.de, anton.ivanov@cambridgegreys.com,
 mattst88@gmail.com, krypton@ulrich-teichert.org, rostedt@goodmis.org,
 David.Laight@ACULAB.COM, richard@nod.at, mjguzik@gmail.com,
 jon.grimm@amd.com, bharata@amd.com, boris.ostrovsky@oracle.com,
 konrad.wilk@oracle.com
References: <20240213055554.1802415-1-ankur.a.arora@oracle.com>
 <15fcf98c-58c5-fa08-2e21-f3b0baf058e6@amd.com> <87zfvtg2mh.ffs@tglx>
From: Raghavendra K T <raghavendra.kt@amd.com>
In-Reply-To: <87zfvtg2mh.ffs@tglx>
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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?
> 
>> 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.
> 

Hello Thomas, Ankur,

Because of high stdev I saw with the runs for Graph500, continued to 
take results with more iterations.

Here is the result. It does not look like there is a concern here.

(you can see the *min* side of preempt-auto case which could have got 
the negative result in the analysis, But I should have posted stdev 
along with that. Sorry for not being louder there.).

Overall this looks good. some time better but all within noise level.

Benchmark = Graph500

x  6.7.0+
+  6.7.0-preempt-auto+

     N           Min           Max        Median           Avg        Stddev
x  15 6.7165689e+09 7.7607743e+09 7.2213638e+09 7.2759563e+09 3.3353312e+08
+  15 6.4856432e+09  7.942607e+09 7.3115082e+09 7.3386124e+09 4.6474773e+08

No difference proven at 80.0% confidence
No difference proven at 95.0% confidence
No difference proven at 99.0% confidence

Thanks and Regards
- Raghu