[LU-4820] extra memcpy in read path

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.8.0
• Affects Version/s: Lustre 2.4.1, Lustre 2.5.0, Lustre 2.6.0, Lustre 2.4.2, Lustre 2.5.1, Lustre 2.5.2, Lustre 2.4.3
• Labels: llnl
• Environment: ZFS
• Severity: 3
• Assignee: Alex Zhuravlev
• Reporter: Alex Zhuravlev

Description

osd_read_prep() in osd-zfs/ calls into dmu_read() which finds the buffers filled osd_bufs_get_read(). this is not needed and cost us extra memcpy() on all the reads.

Issue Links

• is related to: LU-5278 ZFS - many OST watchdogs with IOR

Comments

[Alex Zhuravlev]

any objections to close the ticket?

[Alex Zhuravlev]

landed to master

[Gerrit Updater]

Oleg Drokin ([e-mail]) merged in patch http://review.whamcloud.com/12991/
Subject: LU-4820 osd: drop memcpy in zfs osd
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: b59942cce0ed3b720ec38c3b5a25063d01b8d218

[Alex Zhuravlev]

my bad, sorry folks. please check another version.

[Gerrit Updater]

Alex Zhuravlev ([e-mail]) uploaded a new patch: http://review.whamcloud.com/13929
Subject: LU-4820 osd: drop memcpy in zfs osd
Project: fs/lustre-release
Branch: b2_5
Current Patch Set: 1
Commit: 7651c21a917f672e031a6d4611e563f530e4ec96

[Rick Wagner (Inactive)]

Thanks, Alex. Unfortunately, it looks as though there may be a dependency on other changes. The build failed looking for something in the niobuf_local structure.

In function 'osd_read_prep':
/var/lib/jenkins/workspace/lustre-reviews/arch/x86_64/build_type/server/distro/el6/ib_stack/inkernel/BUILD/BUILD/lustre-2.5.3/lustre/osd-zfs/osd_io.c:759: error: 'struct niobuf_local' has no member named 'lnb_rc'

[Alex Zhuravlev]

RIck, please have a look: http://review.whamcloud.com/13907

[Gerrit Updater]

Alex Zhuravlev ([e-mail]) uploaded a new patch: http://review.whamcloud.com/13907
Subject: LU-4820 osd: drop memcpy in zfs osd
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: a65b20245b874cb20dd0b154e466547d15542730

[Rick Wagner (Inactive)]

Alex,

Can you see how much work it would be to write a patch for this against b2_5? For one of our systems, we want to got with the latest 2.5 release, but I'd like to have this patch included.

Thanks,
Rick

[Alex Zhuravlev]

http://review.whamcloud.com/12991