From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leon Romanovsky Subject: Re: [PATCH rdma-core 1/5] util: Add common mmio macros Date: Wed, 19 Apr 2017 08:55:17 +0300 Message-ID: <20170419055517.GH14088@mtr-leonro.local> References: <1492123127-6266-1-git-send-email-jgunthorpe@obsidianresearch.com> <1492123127-6266-2-git-send-email-jgunthorpe@obsidianresearch.com> <20170418172852.GD7181@obsidianresearch.com> <20170418173815.GC14088@mtr-leonro.local> <20170418181736.GF7181@obsidianresearch.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="RDS4xtyBfx+7DiaI" Return-path: Content-Disposition: inline In-Reply-To: <20170418181736.GF7181-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jason Gunthorpe Cc: Yishai Hadas , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "yishaih-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org" , Majd Dibbiny List-Id: linux-rdma@vger.kernel.org --RDS4xtyBfx+7DiaI Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Apr 18, 2017 at 12:17:36PM -0600, Jason Gunthorpe wrote: > On Tue, Apr 18, 2017 at 08:38:15PM +0300, Leon Romanovsky wrote: > > On Tue, Apr 18, 2017 at 11:28:52AM -0600, Jason Gunthorpe wrote: > > > On Tue, Apr 18, 2017 at 06:52:00PM +0300, Yishai Hadas wrote: > > > > > > We could use a hash scheme or something to multiple the lock, but I'm > > > really not sure that 32 bit performance matters to anyone anymore? > > > > In a hard way, I learned that we have a customer who expects that his 3= 2bit > > application will continue to work, so the answer is - no, I care. > > Of course it continues to work. > > Does your customer fit this very narrow definition: > - Would actually upgrade to rdma-core > - 32 bit > - No SSE hardware (any Intel chip capable of PCI-E has SSE hardware) > - Multiple same-provider devices with a single program touching all > devices (single device performance is unchanged) > - Sensitive to the performance difference of a potential spinlock > contention / cache misplacement for ~4 instructions > > It is hard to understand who cares so much about peformance but leaves > a wack on the table by running in 32 bit mode. It doesn't matter if customer cares or not cares about performance. We as a company provided satisfactory numbers to them and would like to ensure that these numbers don't reduce over time. I'm not looking for a performance boost in 32bit environment, but I don't expect decrease either. > > Is this something like x32? We can certainly improve for x32. =46rom the customer ticket, the system is x86 (32 bits). > > PPC32 could also potentially have a path like SSE.. > > Jason --RDS4xtyBfx+7DiaI Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEkhr/r4Op1/04yqaB5GN7iDZyWKcFAlj2+8UACgkQ5GN7iDZy WKcuRw//ZYT+gclZjYgiVNvE1d3hsbB8NcX1rPk3gDENJaU80YXQCmKIVct/MP6K e95OO91jBsgeR3CugTVBCm+9POvmiU62wU22Sj2pRX0vNnnzjSILoxZPwO7Qf9QS vpVjqQ5RCNbPnyer6ljEYH2sEu1lQdo35A1gX/Lgm5wcyK9SskkXnNfrR+he1tZI gG3tmO2f6SHkOSrHS01JoDQ/Qge8FCSG1vxRdwiuNAfY5dh/LyXgsyzEHUUuAIjg ihHcH6qJZT3ppLovr/PBS9ONIH+6pHtF0bX2JBWdG1ik8QokaOFIBBVsMFMK8T14 42I3x3GHIBOTt0cAKtnrxDlwar2crBPb6SDu3/Iqyp3G11kq20ke1b7gTPllkpEX SH6gzT6cGuqSGWQ+8Conyagv8JUrmno7fqBqoPMBM597Jeum1uyukwsT79Wk6wIp miHtZhXnYfALT0K75XYo6HgrUIdGiWfSFuVfNK/NrJf/jIE6crA1OEWHR+DsuWgf QSR2uHPy2bresrU/I+LPI2EMclvglshmmKJLtXzSNAWTbuV/od8Pc57qFIafRQI3 qCMgx4rC7K1xHlbKksYM/wo+4IxT0ui9MvPbuV2cnwvKRhlTPXXd3PSkTLkfvKrG ybZY/tTuxRujWveJFDnWLi6zZgDo4nEZYEAHQYzDpFqnh6NFEqs= =jNUo -----END PGP SIGNATURE----- --RDS4xtyBfx+7DiaI-- -- 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