From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: [PATCH for-next V2 0/9] Add completion timestamping support Date: Mon, 01 Jun 2015 13:00:57 -0400 Message-ID: <1433178057.114391.208.camel@redhat.com> References: <1433074457-26437-1-git-send-email-ogerlitz@mellanox.com> <1433098827.114391.179.camel@redhat.com> <1433157904.114391.188.camel@redhat.com> <20150601164322.GA14391@obsidianresearch.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-ttGeZwMuxA8mrzUtWHhk" Return-path: In-Reply-To: <20150601164322.GA14391-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jason Gunthorpe Cc: Matan Barak , Or Gerlitz , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Amir Vadai , Tal Alon List-Id: linux-rdma@vger.kernel.org --=-ttGeZwMuxA8mrzUtWHhk Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2015-06-01 at 10:43 -0600, Jason Gunthorpe wrote: > On Mon, Jun 01, 2015 at 07:25:04AM -0400, Doug Ledford wrote: >=20 > > attempted abstraction of ibverbs. Passing in the wc struct allows the > > driver to internally allocate a wc struct with extra private elements > > and pass that back to the user, when the user passes it back to > > ibv_get_timestamp the elements are there in the private portion of the > > struct. >=20 > wc structures are allocated by the caller, there is no option for the > driver to create private elements. You're right, the data would have to be housed somewhere in the driver private completion structs (for example, in the CQE the card posts to memory that the driver then massages into a WC). > AFAIK, Christoph's use case is essentially the only meaningful use > case for this feature, generalizing too much may destroy the > performance that is valuable here. I'm not convinced of that. Steve has already spoke up about the timestamps available in cxgb4. Those are very different and yet still highly valuable to someone investigating performance of their RDMA application. --=20 Doug Ledford GPG KeyID: 0E572FDD --=-ttGeZwMuxA8mrzUtWHhk Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAABCAAGBQJVbI/JAAoJELgmozMOVy/dX74P/2P1uhZwSm9ixc21u26oNBdw XF2e9xFAgiyveHoKsiHW/p+33h3WF/0BCCSpVTRQdXbWgtqRpsdPH1XgOr1i4yjy /YLl+fLkvCTJEF7fpRz9uE3oVqwAq/mHC/GDNGvbHi3hXJ7WYzD06mDQRZPIJOW3 9GZEgsJj3jkSvMjV6XZlVbXPJhlcKqxv1woR14JjOOfk7bRTs64XYzICYHWfsNwW brOpSw2pBWagxo9JWqc188cAumaQZ/p0MzYBngjrDkDRT9UDaMHCC7VL+auFrkbB 3N6pL6bPacPDsXv8o3hIn7WliR6676/bzfC+jhqFlsS9O1K7wkNJGb2uu8giYxEn YJ7UPfjj3WTI75xyLye5nSfNj+4nALj6zqzuIo1n6VCLFQbUF+262+0TujcL6oRk 01DR0Z0V+ryYJ1/+BHWt2lKyhsscsU0e/QB1fa62v4kD3ECHDZ0Ltu0T3NsLhAMH YsH+4SdA7uxM9YoQqyh1KGEW5zHkJAHnXD6fT2o+rhTgZO8hmZTWdWAWxj1ms5sF KA4zTjUx6ss97dKBdGj/KASL/YcpM22R4RsgXjlxJs0vPlvJw3zsnsf3pXKM0TWz mZuzud6W547KUx9vgPGbc6DcfYcg5CKokJnytpQbjidngqvndp3kQYxtSDi5nwNJ orkOWiquLdIZVUNwTIl3 =mLPB -----END PGP SIGNATURE----- --=-ttGeZwMuxA8mrzUtWHhk-- -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html