[LU-1422] Cleanup Lustre cray specific code

• Type: Improvement
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.3.0, Lustre 2.6.0
• Affects Version/s: Lustre 2.3.0
• Environment: Cray nodes running Lustre
• Assignee: Zhenyu Xu
• Reporter: James A Simmons

Description

In the early days of Lustre the cray Catamount system was supported. This required special blocks of code but today CRAY system use a standard Linux system so these special blocks of code are not only might not be needed but could hind performance on the CRAY platform. Such was the case recently uncoverd while doing IR testing. This ticket will be a peer view of what is and is not needed anymore.

Comments

[James A Simmons]

Thanks for the review. Will fix in next addition. I'm going to wait to update the patch due to the LNET rewrite going on in the master branch right now. Once LU-56 is done merging I will update the patch.

[Cory Spitz]

FYI: James also has http://review.whamcloud.com/#change,3064 up for review to remove Cray Catamount support (CRAY_XT3 and the portals ulnd)

[Cory Spitz]

Cray won't be maintaining the SeaStar LNDs any longer. So, we would have no objection to removing it.

[James A Simmons]

Also Cory should we remove the ulnd for sea star?

[James A Simmons]

From looking at the code the CRAY_XT3 is specific to Catamount even for the sea star case. In that case it is most likely safe to removal all the CRAY_XT3 code.

[Cory Spitz]

I wrote, "We may choose to delete Catamount specifics entirely even if they were correct/useful because it is no longer used or supported." After more consideration, Cray is OK with removing the Catamount support.

[Peter Jones]

Bobijam

Could you please review this suggested change?

Thanks

Peter

[James A Simmons]

http://review.whamcloud.com/#change,2835

[James A Simmons]

Perhaps we should just drop the XT3 moniker?

[Cory Spitz]

Thank you, James.

These special sections are conditional on CRAY_XT3. However, some of those changes were specific to CRAY Catamount using liblustre, and others not. Each CRAY_XT3 section should be examined as James suggested, and some will stay and some might go. However, the CRAY_XT3 moniker is outdated and leads to confusion so it should change in the very least. Also, for the changes that stay, we should be clear whether they are for Cray Lustre on Linux or Catamount (EOL/deprecated). We may choose to delete Catamount specifics entirely even if they were correct/useful because it is no longer used or supported.