From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sagi Grimberg Subject: Re: [PATCH v1 3/9] xprtrdma: Introduce ro_unmap_sync method Date: Tue, 24 Nov 2015 16:44:28 +0200 Message-ID: <565477CC.5070309@dev.mellanox.co.il> References: <20151123220627.32702.62667.stgit@manet.1015granger.net> <20151123221414.32702.87638.stgit@manet.1015granger.net> <20151124064556.GA29141@infradead.org> <565442F5.7080400@dev.mellanox.co.il> <4B2D7C66-31AC-44F3-A8CC-22CC7136015C@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <4B2D7C66-31AC-44F3-A8CC-22CC7136015C-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Chuck Lever Cc: Christoph Hellwig , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linux NFS Mailing List , Sagi Grimberg List-Id: linux-rdma@vger.kernel.org Hey Chuck, > >> It is painful, too painful. The entire value proposition of RDMA is >> low-latency and waiting for the extra HW round-trip for a local >> invalidation to complete is unacceptable, moreover it adds a huge lo= ads >> of extra interrupts and cache-line pollutions. > > The killer is the extra context switches, I=92ve found. That too... > I=92ve noticed only a marginal loss of performance on modern > hardware. Would you mind sharing your observations? -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html