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: Wed, 10 Jun 2015 19:54:37 -0400 Message-ID: <1433980477.71666.57.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> <1433255724.114391.225.camel@redhat.com> <20150602180844.GD17776@obsidianresearch.com> <1828884A29C6694DAF28B7E6B8A82373A8FE4F16@ORSMSX109.amr.corp.intel.com> <20150604164759.GC27699@obsidianresearch.com> <1828884A29C6694DAF28B7E6B8A82373A8FE4F98@ORSMSX109.amr.corp.intel.com> <1828884A29C6694DAF28B7E6B8A82373A8FE5AB8@ORSMSX109.amr.corp.intel.com> <5577F93F.9030405@mellanox.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-Xw6l7QBzqloDBS5dfqEZ" Return-path: In-Reply-To: <5577F93F.9030405-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Or Gerlitz Cc: Christoph Lameter , "Hefty, Sean" , Jason Gunthorpe , Matan Barak , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Amir Vadai , Tal Alon List-Id: linux-rdma@vger.kernel.org --=-Xw6l7QBzqloDBS5dfqEZ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2015-06-10 at 11:45 +0300, Or Gerlitz wrote: > On 6/10/2015 4:26 AM, Christoph Lameter wrote: > >> >I have no problem with a bare metal interface exposing this. But pre= tendin=3D > >> >g that it's generic and that this is the one and only way that this c= ould b=3D > >> >e implemented doesn't make it so. > > This is a way it was implemented and its usable. Shooting for pie in th= e > > sky does not bring us anything. Nor ideas of requirements from a new > > experimental API that does not support the basic features that we need > > and seems to be on its way to mess up the latencies of access to RDMA o= perations. >=20 > Doug, >=20 > What's your maintainer say here? >=20 > The current proposal has: >=20 > 1. raw HCA clock completion generation time-stamp for CQEs > 2. HCA clock frequency in KHZ > 3. mask telling how many bits are relevant from the 64bit time-stamp >=20 > This is fairly simple, practical and very much usable to FSI=20 > applications and users, and can be extended later if someone comes up=20 > with better/other combination of the frequency/mask. Have a GO? This is all related to the kernel <-> libibverbs interface. In that regard, I'm fine with what we have here. To be more specific, the CQ creation flags and use of create_cq_ex and the extension of the query_device struct and use of extended query device are really the only user visible items here, and I'm OK with those. None of these items are hot path items and structure growth with new fields is not the major item it is for the wc struct. Now, the change to the wc struct and the change to ibv_poll_cq are more important and still need some work to get to a final implementation IMO. But that work is all limited to libibverbs and doesn't impact this kernel patchset. --=20 Doug Ledford GPG KeyID: 0E572FDD --=-Xw6l7QBzqloDBS5dfqEZ 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 iQIcBAABCAAGBQJVeM49AAoJELgmozMOVy/d2g4P/0LB4ICCaFkWNXJC1Qrjy3/5 rB92FKaILk5GqoL96vdEfDFy5G694UI+Wjyl3dzK1Bj6b/a1JMWoKCTp2FmWoHDN ELsfFkvS32mLTI0885O0t3Xmdc0Cnz2KK41qQJO8g+xg57Nd0gOEKGswLFwB1aHj zInWPR7AsU+UDEZnoo1UK4u6hgCfjkiw4S+QkG5KXF+6wVtDxL3I/sfSv+kzAZ1J PpVuJtmdCLoKKHsODENOIVABXeX+2w8Fk0Hm8f/UOdDsDuC3RcG2sKeueS1sMNX7 /B0n+XE2NqujlpKHI+7SV2tPosgsMsVs43SCcRdG5/I2XA59d7AE15UaXxOK1Uo7 jhHMeIL47q5f+ATqsNcQgGEzBbdr7z4QkTYj0apbVdUSQJNkCxEAPZZiz+scJjBd m2PPPhg5CAxHgznsgt0S9RuxciL2jW379np+Fxoept5J8Om93JyKWEQW3ieK7MZo slA+aspTVFVhRQ/Gc2guajTOYH9Qxq84k38uMrwNeHo6/nIr5Z06Q2h1cGQtsT+F Y056JAZPNxyDDyHOZQiEUJV7EAZpTp+lrCSHWo4bCoc9fZDS+FnfwkDjFAKZ+u3B V5qYKX6MtmQFKwAO+d/BcdwMMOPzvu9ouRykezYbU5qXp1uip9X1PecRe9V/+6x7 gUFGUNOTnRlMqBw7/OOc =nalC -----END PGP SIGNATURE----- --=-Xw6l7QBzqloDBS5dfqEZ-- -- 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