--- Bernard Metzler, PhD Tech. Leader High Performance I/O, Principal Research Staff IBM Zurich Research Laboratory Saeumerstrasse 4 CH-8803 Rueschlikon, Switzerland +41 44 724 8605 -----"Steve Wise" <swise@xxxxxxxxxxxxxxxxxxxxx> wrote: ----- >To: "'Jason Gunthorpe'" <jgg@xxxxxxxx> >From: "Steve Wise" <swise@xxxxxxxxxxxxxxxxxxxxx> >Date: 01/23/2018 05:58PM >Cc: "'Bernard Metzler'" <bmt@xxxxxxxxxxxxxx>, ><linux-rdma@xxxxxxxxxxxxxxx> >Subject: RE: [PATCH v3 03/13] Attach/detach SoftiWarp to/from network >and RDMA subsystem > >> >> On Tue, Jan 23, 2018 at 10:33:48AM -0600, Steve Wise wrote: >> >> > > +/* Restrict usage of GSO, if hardware peer iwarp is unable to >process >> > > + * large packets. gso_seg_limit = 1 lets siw send only packets >up to >> > > + * one real MTU in size, but severly limits maximum bandwidth. >> > > + * gso_seg_limit = 0 makes use of GSO (and more than doubles >throughput >> > > + * for large transfers). >> > > + */ >> > > +const int gso_seg_limit; >> > > + >> > >> > The GSO configuration needs to default to enable interoperation >with all >> > vendors (and comply with the RFCs). So make it 1 please. >> >> The thing we call GSO in the netstack should be totally transparent >on >> the wire, so at the very least this needs some additional >elaboration. >> > >From: >https://urldefense.proofpoint.com/v2/url?u=https-3A__tools.ietf.org_h >tml_rfc5041-23section-2D5.2&d=DwICAg&c=jf_iaSHvJObTbx-siA1ZOg&r=2TaYX >Q0T-r8ZO1PP1alNwU_QJcRRLfmYTAgd3QCvqSc&m=maNYrMpuQjDoXG0NADT5M-LhIwmL >KrmFzWtWh4J3sAc&s=ZDYAQqhyaTuRtFqQpA95k0oT6ildygWkkmJ3fqIWNzU&e= > >"At the Data Source, the DDP layer MUST segment the data contained in > a ULP message into a series of DDP Segments, where each DDP >Segment > contains a DDP Header and ULP Payload, and MUST be no larger than >the > MULPDU value Advertised by the LLP." TCP advertises 64k on the kernel socket ;) -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
