Question about JDK-8221092

[Viswanathan, Sandhya]

Hi Taizo,

UseAVX is set to 2 for all Skylake processors (cupid family=6, model=0x55, stepping < 5) , not just Skylake X.
CascadeLake processors have cupid family=6, model=0x55, stepping >=5.

Hope this helps.

Best Regards,
Sandhya

-------- Forwarded Message --------
Subject: 	Re: Question about JDK-8221092
Date: 	Wed, 10 Jul 2024 06:39:43 +0000
From: 	Taizo Kurashige (Fujitsu) <kurashige.taizo at fujitsu.com>
To: 	hotspot-compiler-dev at openjdk.org <hotspot-compiler-dev at openjdk.org>



Hi all,

Could someone please respond to this question if possible?

Thank you.

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Taizo Kurashige
GitHub account : https://github.com/kurashige23 <https://github.com/kurashige23>
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*差出人:* Kurashige, Taizo/倉繁 泰三
*送信日時:* 2024年7月3日 15:09
*宛先:* hotspot-compiler-dev at openjdk.org <hotspot-compiler-dev at openjdk.org>
*件名:* Question about JDK-8221092
Hi all,
I have a question about https://bugs.openjdk.org/browse/JDK-8221092.
If possible, could someone please provide some insight?

Here's what I would like to know:

1. Is it correct to understand that "Skylake (X7) processors" refers to the Skylake processors listed at https://ark.intel.com/content/www/us/en/ark/products/codename/37572/products-formerly-skylake.html, specifically those in the 7000 series with an "X" or "XE" in their names? For example, "Intel® Core™ i9-7920X X-series Processor (16.5M Cache, up to 4.30 GHz)" or "Intel® Core™ i9-7980XE Extreme Edition Processor (24.75M Cache, up to 4.20 GHz)".

2. In the fix for JDK-8221092, if the stepping is less than 5, the processor is considered to be of Skylake (X7) or an earlier version. In such cases, UseAVX is set to 2. Is there any documentation that the stepping for Skylake (X7) is 5?

Thank you.


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Taizo Kurashige
GitHub account : https://github.com/kurashige23 <https://github.com/kurashige23> <https://github.com/kurashige23>
	
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