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Bug #1122

kclient: async readahead

Added by Sage Weil almost 9 years ago. Updated over 8 years ago.

Status:
Resolved
Priority:
Normal
Assignee:
Category:
-
Target version:
% Done:

0%

Source:
Tags:
Backport:
Regression:
No
Severity:
3 - minor
Reviewed:
Affected Versions:
ceph-qa-suite:
Pull request ID:
Crash signature:

Description

Many people now have noticed that sequential read performance is slower than writes. Is this simply a matter of adjusting readahead defaults, or is something else going on?

History

#1 Updated by Sage Weil almost 9 years ago

  • translation missing: en.field_story_points set to 5
  • translation missing: en.field_position set to 685

#2 Updated by Sage Weil almost 9 years ago

  • translation missing: en.field_position deleted (683)
  • translation missing: en.field_position set to 17

#3 Updated by Sage Weil almost 9 years ago

  • Target version changed from v0.30 to v0.31

#4 Updated by Sage Weil almost 9 years ago

  • translation missing: en.field_story_points changed from 5 to 8
  • translation missing: en.field_position deleted (27)
  • translation missing: en.field_position set to 27

#5 Updated by Sage Weil almost 9 years ago

  • translation missing: en.field_position deleted (26)
  • translation missing: en.field_position set to 701

#6 Updated by Sage Weil almost 9 years ago

  • Target version changed from v0.31 to v0.32

#7 Updated by Sage Weil almost 9 years ago

  • translation missing: en.field_position deleted (704)
  • translation missing: en.field_position set to 11

#8 Updated by Sage Weil over 8 years ago

see #804

#9 Updated by Sage Weil over 8 years ago

  • Target version changed from v0.32 to v0.33
  • translation missing: en.field_position deleted (41)
  • translation missing: en.field_position set to 1

#10 Updated by Sage Weil over 8 years ago

  • Subject changed from slow read performance to kclient: async readahead
  • translation missing: en.field_position deleted (1)
  • translation missing: en.field_position set to 1

#11 Updated by Sage Weil over 8 years ago

  • Assignee set to Sage Weil

#12 Updated by Sage Weil over 8 years ago

  • Status changed from New to Resolved

I'm seeing significantly better performance on sepia. E.g. for 8 osds/1 client, kclient reads saturate the interface (around 117 MB/sec) while cfuse reads get about 70 MB/sec.

Before the changes I see 91 MB/sec (with the same cluster/nodes).

dd if=/dev/zero of=foo bs=1M count=10000
for f in `seq 1 10` ; do dd if=foo of=/dev/null bs=1M ; done

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