On Tue, Aug 8, 2017 at 8:31 AM, John Fastabend <john.fastab...@gmail.com> 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 >
