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Bug #9217

wrong value of osd::op_w_latency

Added by Xinxin Shu almost 5 years ago. Updated almost 5 years ago.

Status:
Resolved
Priority:
Normal
Assignee:
Category:
OSD
Target version:
-
Start date:
08/25/2014
Due date:
% Done:

0%

Source:
Community (dev)
Tags:
Backport:
Regression:
No
Severity:
3 - minor
Reviewed:
Affected Versions:
ceph-qa-suite:
Pull request ID:

Description

when i use fio to test rbd performance (4kb random write) , i found that osd::op_w_latency which i got from perf counter is much larger than the latency reported by fio, after i digged into it and found that, with XFS , after data is written to journal , osd sends a reply to client to imply that the write request has completed , it updates the osd::op_w_latency perf counter in ReplicatedPG::eval_repop function , when data is written to filestore, the osd::op_w_latency perf counter updates again, so op_w_latency perf counter records the apply latency , not the commit latency , is this the defined behavior or a bug?

Associated revisions

Revision f3bf2468 (diff)
Added by xinxin shu almost 5 years ago

fix wrong value of op_w_latency perf counter

Fixes: #9217

Signed-off-by: xinxin shu <>

History

#1 Updated by Xinxin Shu almost 5 years ago

  • Category set to OSD

#2 Updated by Sage Weil almost 5 years ago

  • Source changed from other to Community (dev)

I think it's a bug:

  osd_plb.add_time_avg(l_osd_op_w_rlat, "op_w_rlat");   // client write readable/applied latency
  osd_plb.add_time_avg(l_osd_op_w_lat,  "op_w_latency");    // client write latency

#3 Updated by Xinxin Shu almost 5 years ago

  • Assignee set to Xinxin Shu

#4 Updated by Xinxin Shu almost 5 years ago

  • Status changed from New to Need Review

#6 Updated by Sage Weil almost 5 years ago

  • Status changed from Need Review to Resolved

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