From owner-svn-src-head@freebsd.org Fri Jan 24 01:25:07 2020 Return-Path: Delivered-To: svn-src-head@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id F0EE722A802; Fri, 24 Jan 2020 01:25:07 +0000 (UTC) (envelope-from glebius@freebsd.org) Received: from cell.glebi.us (glebi.us [162.251.186.162]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "cell.glebi.us", Issuer "cell.glebi.us" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 483hJz2R6tz4KfB; Fri, 24 Jan 2020 01:25:06 +0000 (UTC) (envelope-from glebius@freebsd.org) Received: from cell.glebi.us (localhost [127.0.0.1]) by cell.glebi.us (8.15.2/8.15.2) with ESMTPS id 00O1OwvH009001 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Thu, 23 Jan 2020 17:24:58 -0800 (PST) (envelope-from glebius@freebsd.org) Received: (from glebius@localhost) by cell.glebi.us (8.15.2/8.15.2/Submit) id 00O1OwVt009000; Thu, 23 Jan 2020 17:24:58 -0800 (PST) (envelope-from glebius@freebsd.org) X-Authentication-Warning: cell.glebi.us: glebius set sender to glebius@freebsd.org using -f Date: Thu, 23 Jan 2020 17:24:58 -0800 From: Gleb Smirnoff To: Ryan Stone Cc: src-committers , svn-src-all , svn-src-head Subject: Re: svn commit: r357051 - head/sys/dev/bge Message-ID: <20200124012458.GI1268@FreeBSD.org> References: <202001231636.00NGawrr080128@repo.freebsd.org> <20200123230546.GG1268@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.2 (2019-09-21) X-Rspamd-Queue-Id: 483hJz2R6tz4KfB X-Spamd-Bar: / Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-0.84 / 15.00]; local_wl_from(0.00)[freebsd.org]; NEURAL_HAM_MEDIUM(-0.87)[-0.874,0]; NEURAL_SPAM_LONG(0.03)[0.029,0]; ASN(0.00)[asn:27348, ipnet:162.251.186.0/24, country:US] X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Jan 2020 01:25:08 -0000 On Thu, Jan 23, 2020 at 08:17:46PM -0500, Ryan Stone wrote: R> On Thu, Jan 23, 2020 at 6:05 PM Gleb Smirnoff wrote: R> > R> > On Thu, Jan 23, 2020 at 02:17:33PM -0500, Ryan Stone wrote: R> > R> What is a driver's responsibility now for entering/leaving the net epoch now? R> > R> > For drivers that are 'special', entering the net epoch is necessary. Special R> > usually means running if_input outside network interrupt context. R> > R> > However, there is plan to generalize entering/exiting epoch for taskqueues R> > and callouts. R> R> Why on earth is it done that way rather than putting the network epoch R> enter/exit in ether_input? I'm with Ian; this sounds like a huge R> layering violation. Because at interrupt level we can batch multiple packets in a single epoch. This speeds up unfiltered packet forwarding performance by 5%. With driver level pfil hooks I would claim even more improvement, because before the change we needed to enter epoch twice - once for filtering, than for ether_input. Epoch isn't a layer, it is a synchronisation primitive, so I disagree about statement on layering violation. -- Gleb Smirnoff