FIO with fsync option issues more DDIR_SYNC commands than expected #1754
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Issue and root cause: When fsync option is used, the number of flush (or DDIR_SYNC) commands issued is more than the expected number of flush commands. To elaborate: - In the fio config file, consider fsync=1 1. FIO issues 1 write command 2. After write completes, FIO sets last_was_sync variable to false 3. FIO issues 1 flush command 4. FIO keeps issuing flush commands since last_was_sync is still false and this causes more flush commands to be issued than expected 5. last_was_sync is set to true after the flush command completes - The above steps repeats until the workload is completed. Fix: Instead of setting last_was_sync to true after flush command is completed and setting last_was_sync to false after write command is completed, set last_was_sync to true after flush command is issued and set last_was_sync to false after write command is issued. Signed-off-by: Celestine Chen [email protected]
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FIO with fsync option issues more DDIR_SYNC commands than expected
Issue and root cause
When fsync option is used, the number of flush (or DDIR_SYNC) commands
issued is more than the expected number of flush commands.
To elaborate:
and this causes more flush commands to be issued than expected
Fix
Instead of setting last_was_sync to true after flush command is completed
and setting last_was_sync to false after write command is completed,
set last_was_sync to true after flush command is issued and set
last_was_sync to false after write command is issued.
Signed-off-by: Celestine Chen [email protected]