Bug #1122
kclient: async readahead
Source:
Tags:
Backport:
Regression:
No
Severity:
3 - minor
Reviewed:
Affected Versions:
ceph-qa-suite:
Pull request ID:
Crash signature (v1):
Crash signature (v2):
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 13 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 13 years ago
- translation missing: en.field_position deleted (
683) - translation missing: en.field_position set to 17
#3 Updated by Sage Weil almost 13 years ago
- Target version changed from v0.30 to v0.31
#4 Updated by Sage Weil almost 13 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 13 years ago
- translation missing: en.field_position deleted (
26) - translation missing: en.field_position set to 701
#6 Updated by Sage Weil almost 13 years ago
- Target version changed from v0.31 to v0.32
#7 Updated by Sage Weil over 12 years ago
- translation missing: en.field_position deleted (
704) - translation missing: en.field_position set to 11
#8 Updated by Sage Weil over 12 years ago
see #804
#9 Updated by Sage Weil over 12 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 12 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 12 years ago
- Assignee set to Sage Weil
#12 Updated by Sage Weil over 12 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