From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Fastabend Subject: Re: [PATCH v3 net-next 0/5] ulp: Generalize ULP infrastructure Date: Tue, 08 Aug 2017 12:30:14 -0700 Message-ID: <598A1146.9090205@gmail.com> References: <20170807172818.31855-1-tom@quantonium.net> <5989D958.6080506@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: Tom Herbert , Linux Kernel Network Developers , Rohit Seth , Dave Watson To: Tom Herbert Return-path: Received: from mail-pg0-f66.google.com ([74.125.83.66]:37948 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752037AbdHHTa2 (ORCPT ); Tue, 8 Aug 2017 15:30:28 -0400 Received: by mail-pg0-f66.google.com with SMTP id 123so3890959pga.5 for ; Tue, 08 Aug 2017 12:30:28 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On 08/08/2017 10:04 AM, Tom Herbert wrote: > 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. > OTOH these optimizations are usually easiest to do at the beginning. And building an enum of ULP types would allow removing string comparisons and to do simpler unsigned comparisons. I wont complain too much here though because this series didn't introduce the lists. > Tom > >> Thanks, >> .John >>