From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============0610753924746388508==" MIME-Version: 1.0 From: Jonas Pfefferle Subject: [SPDK] NVMe command ordering Date: Fri, 23 Mar 2018 10:04:11 +0100 Message-ID: List-ID: To: spdk@lists.01.org --===============0610753924746388508== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Hi @all, Can anyone clarify this for me: NVMe spec 6.3 Command Ordering Requirements "For all commands which are not part of a fused operation (refer to section = 4.10), or for which the write size is greater than AWUN, each command is = processed as an independent entity without reference to other=C2=A0commands = submitted to the same I/O Submission Queue or to commands submitted to othe= r = I/O=C2=A0Submission Queues" So writes <=3D AWUN size are atomic but there is no ordering between the = commands, e.g. write command A issued before write command B to the same LB= A = can be executed in order AB or BA, the only thing guaranteed is that they = are executed atomically? And there is no way to enforce ordering except on = the host side? Regards, Jonas --===============0610753924746388508==--