pt-diskstats: rd_avkb & wr_avkb derived incorrectly
Bug #872699 reported by
Aurimas Mikalauskas
This bug affects 2 people
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Percona Toolkit moved to https://jira.percona.com/projects/PT |
Fix Released
|
Medium
|
Brian Fraser |
Bug Description
/proc/diskstats displays sectors read and sectors written in columns #6 and #10. Sectors are typically 512b units, however pt-diskstats assumes one sector = 1kb. Therefore, it would be best either to rename them to "rd_avsct" and "wr_avsct", or divide the number by 2 to display kilobytes.
Here's a sample that clearly shows that numbers do not add up. I've written 1MB with dd using oflag=direct bs=131072 count=8:
#ts device rd_s rd_avkb rd_mb_s rd_mrg rd_cnc rd_rt wr_s wr_avkb wr_mb_s wr_mrg wr_cnc wr_rt busy in_prg
{1} sdb 0.0 0.0 0.0 0% 0.0 0.0 7.9 256.0 1.0 0% 0.0 0.0 0% 0
Thank you,
Aurimas
Related branches
description: | updated |
tags: | added: pt-diskstats |
tags: |
added: wrong-value removed: doc |
Changed in percona-toolkit: | |
importance: | Undecided → Medium |
milestone: | none → 2.0-beta2 |
Changed in percona-toolkit: | |
status: | New → Confirmed |
tags: |
added: wrong-output removed: wrong-value |
Changed in percona-toolkit: | |
assignee: | nobody → Brian Fraser (fraserbn) |
Changed in percona-toolkit: | |
status: | Confirmed → Fix Committed |
Changed in percona-toolkit: | |
status: | Fix Committed → Fix Released |
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Let's keep the column name as-is and fix the math.