From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Herbert Subject: Re: [PATCH v3 net-next 0/5] ulp: Generalize ULP infrastructure Date: Tue, 8 Aug 2017 10:04:38 -0700 Message-ID: References: <20170807172818.31855-1-tom@quantonium.net> <5989D958.6080506@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Tom Herbert , Linux Kernel Network Developers , Rohit Seth , Dave Watson To: John Fastabend Return-path: Received: from mail-wm0-f51.google.com ([74.125.82.51]:37881 "EHLO mail-wm0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752092AbdHHREk (ORCPT ); Tue, 8 Aug 2017 13:04:40 -0400 Received: by mail-wm0-f51.google.com with SMTP id t201so12305333wmt.0 for ; Tue, 08 Aug 2017 10:04:39 -0700 (PDT) In-Reply-To: <5989D958.6080506@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Aug 8, 2017 at 8:31 AM, John Fastabend wrote: > On 08/07/2017 10:28 AM, Tom Herbert wrote: >> Generalize the ULP infrastructure that was recently introduced to >> support kTLS. This adds a SO_ULP socket option and creates new fields in >> sock structure for ULP ops and ULP data. Also, the interface allows >> additional per ULP parameters to be set so that a ULP can be pushed >> and operations started in one shot. >> >> In this patch set: >> - Minor dependency fix in inet_common.h >> - Implement ULP infrastructure as a socket mechanism >> - Fixes TCP and TLS to use the new method (maintaining backwards >> API compatibility) >> - Adds a ulp.txt document >> >> Tested: Ran simple ULP. Dave Watson verified kTLS works. >> >> -v2: Fix compilation errors when CONFIG_ULP_SOCK not set. >> -v3: Fix one more build issue, check that sk_protocol is IPPROTO_TCP >> in tsl_init. Also, fix a couple of minor issues related to >> introducing locked versions of sendmsg, send page. Thanks to >> Dave Watson, John Fastabend, and Mat Martineau for testing and >> providing fixes. >> > > > Hi Tom, Dave, > > I'm concerned about the performance impact of walking a list and > doing string compares on every socket we create with kTLS. Dave > do you have any request/response tests for kTLS that would put pressure > on the create/destroy time of this infrastructure? We should do some > tests with dummy entries in the ULP list to understand the impact of > this list walk. > > I like the underlying TCP generalized hooks, but do we really expect a > lot of these hooks to exist? If we only have two on the roadmap > (kTLS and socktap) it seems a bit overkill. Further, if we really expect > many ULP objects then the list walk and compare will become more expensive > perhaps becoming noticeable in request per second metrics. > > Why not just create another socktap socketopt? That will be better from > complexity and likely performance sides. > IMO, given that there is at most two even proposed at this point I don't there's much point addressing performance. When ULP feature catches on and we start see a whole bunch of them then it's straightforward to use a hash table or some more efficient mechanism. Tom > Thanks, > .John >