From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexei Starovoitov Subject: Re: [RFC 12/12] nfp: bpf: add denser mode of execution Date: Wed, 1 Jun 2016 15:01:16 -0700 Message-ID: <20160601220114.GC24671@ast-mbp.thefacebook.com> References: <1464799814-4453-1-git-send-email-jakub.kicinski@netronome.com> <1464799814-4453-13-git-send-email-jakub.kicinski@netronome.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, dinan.gunawardena@netronome.com To: Jakub Kicinski Return-path: Received: from mail-pa0-f52.google.com ([209.85.220.52]:36633 "EHLO mail-pa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751527AbcFAWBV (ORCPT ); Wed, 1 Jun 2016 18:01:21 -0400 Received: by mail-pa0-f52.google.com with SMTP id eu11so76892pad.3 for ; Wed, 01 Jun 2016 15:01:21 -0700 (PDT) Content-Disposition: inline In-Reply-To: <1464799814-4453-13-git-send-email-jakub.kicinski@netronome.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Jun 01, 2016 at 05:50:14PM +0100, Jakub Kicinski wrote: > If BPF uses less than 7 registers programmable engines > can process twice as many packets in parallel. Signal > this denser mode of operation to FW by setting the lowest > bit in DMA address of the machine code buffer. > > Signed-off-by: Jakub Kicinski > Reviewed-by: Dinan Gunawardena > Reviewed-by: Simon Horman wow. that sounds pretty cool. I was about to ask whether we can help HW to be more efficient by doing something on bpf side like annotating the registers or adding 'hw_only' registers... but looks like less registers is actually good, since NFP jit can parallelize it? Truly wow. if you can share the hw architecture details and explain more on how this 'dense_mode' works, would be awesome.