Would still be beneficial to have async fsync even with O_DIRECT

Posted May 31, 2017 20:20 UTC (Wed) by sitsofe (guest, #104576)
In reply to: Toward non-blocking asynchronous I/O by ringerc
Parent article: Toward non-blocking asynchronous I/O

O_DIRECT implies that the I/O won't be left rolling around in the OS' cache but says nothing about whether it is still in the disk device's non-volatile cache. You could send all I/Os down with O_SYNC too but speeds will plummet. Thus it's still desirable to be able to send down an fsync (and it would have been preferable if submitting it didn't have to block)...