A github link is included in the JIRA issue to articulate the use case, https://jira.fd.io/browse/VPP-1967
The github link has a value for a classifier entry shown: https://github.com/FDio/vpp/pull/33 The value is a value used in a 5G UPF. The classifier entry's metadata cannot support such a value. Thanks for the pool of values idea. Yes, if vlib_buffer_t is not modified, I will incur another lookup. Best wishes, Hemant -----Original Message----- From: Benoit Ganne (bganne) <bga...@cisco.com> Sent: Wednesday, January 20, 2021 5:23 AM To: Neale Ranns <ne...@graphiant.com>; hem...@mnkcg.com; ayour...@gmail.com Cc: vpp-dev@lists.fd.io Subject: RE: [vpp-dev] classifier howto? Maybe the 1st question should be what is your usecase here? What is the 64-bits used for? It would be better to rely on the already-existing u32 opaque_index instead. If you really need a u64 value, you can always get away with it by using a pool of u64 values indexed by opaque_index, and look up the 64-bits value via pool_elt_at_index(p, opaque_index) in the dataplane. Best ben > -----Original Message----- > From: vpp-dev@lists.fd.io <vpp-dev@lists.fd.io> On Behalf Of Neale > Ranns > Sent: mercredi 20 janvier 2021 10:18 > To: hem...@mnkcg.com; ayour...@gmail.com > Cc: vpp-dev@lists.fd.io > Subject: Re: [vpp-dev] classifier howto? > > Hi Hemant, > > > > I’ll be a little more direct 😊 you can’t expand the size of opaque. > The blast radius of such a change is just too large. > > Your alternative choices are: 1) use oqaque2, 2) overlay your ‘value’ > field in the union in opaque. The latter is preferable since you won’t > incur the cost of loading the other cacheline, but you will need to be > sure that the value remains valid (i.e. is not overwritten) by > intermediate nodes from the time it is set to the time it is used. > > > > /neale > > > > > > > > From: vpp-dev@lists.fd.io <vpp-dev@lists.fd.io> on behalf of hemant > via lists.fd.io <hemant=mnkcg....@lists.fd.io> > Date: Wednesday, 20 January 2021 at 02:51 > To: ayour...@gmail.com <ayour...@gmail.com> > Cc: vpp-dev@lists.fd.io <vpp-dev@lists.fd.io> > Subject: Re: [vpp-dev] classifier howto? > > Andrew, > > > > The good thing with the code changes are that the changes are common > to any plugin or base code tests. Any CSIT testing could take the > diffs and test for sanity. > > > > I also wonder when the opaque2 member (line of code below) was added > to vlib_buffer_t the cache line got impacted by a factor larger than > 2 to 3 cache lines of these changes. > > > > https://github.com/FDio/vpp/blob/5c1e48c01b50ddbd7623228e3dbc94d835d23 > 813/ > src/vlib/buffer.h#L170 > > > > Anyone recall the perf changes with opaque2? > > > > For my traffic setup (uses trex and 10G NICs) and a UPF IPv4 test, I > don’t see appreciable difference testing traffic with our without the > code changes. > > > > Thanks, > > > > Hemant > > > > From: Andrew 👽 Yourtchenko <ayour...@gmail.com> > Sent: Tuesday, January 19, 2021 6:21 PM > To: hem...@mnkcg.com > Cc: vpp-dev@lists.fd.io > Subject: Re: [vpp-dev] classifier howto? > > > > the further discussion to be held in 30844 with the corresponding > SMEs, but in my cursory virw it’s tweaking the buffer metadata area > which is quite erformance critical - and if I read well > https://gerrit.fd.io/r/c/vpp/+/30844/2/src/vlib/buffer.h#194 increases > the per-buffer metadata size from 2 to 3 cache lines... what is the > performance impact of this change for all of the existing functions? > (Might make sense to proactively include this analysis into 30844, > since I’d expect it the very first question to be asked during the review). > > > > --a > > > > > > > On 20 Jan 2021, at 00:06, hem...@mnkcg.com <mailto:hem...@mnkcg.com> > wrote: > > > > Andrew, > > > > Sorry, I am used to github which auto-merges two commits and missed > using gerrit ‘s –amend in my 2nd commit. I did what you unicasted to > me and now the latest diffs are available in review. > > > > https://gerrit.fd.io/r/c/vpp/+/30848 > > > > thanks, > > > > Hemant > > > > From: vpp-dev@lists.fd.io <mailto:vpp-dev@lists.fd.io> <vpp- > d...@lists.fd.io <mailto:vpp-dev@lists.fd.io> > On Behalf Of Andrew > Yourtchenko > Sent: Tuesday, January 19, 2021 4:40 PM > To: hem...@mnkcg.com <mailto:hem...@mnkcg.com> > Cc: vpp-dev@lists.fd.io <mailto:vpp-dev@lists.fd.io> > Subject: Re: [vpp-dev] classifier howto? > > > > > > > > > > > > On 19 Jan 2021, at 22:17, hem...@mnkcg.com > <mailto:hem...@mnkcg.com> > wrote: > > > > Andrew, > > > > Great suggestion – thanks. I updated the code after taking > care of > your comments. > > > > https://gerrit.fd.io/r/c/vpp/+/30848/1 > > > > Seems like you pushed two different changes - the better approach is > to reuse the “Change-ID: xxxx” value from the previous edit by doing > “git commit —amend”, then the edits show up as the revisions of the > same change. (Which, while being a bit counterintuitive at first, > makes the gerrit workflow more powerful than eg GitHub). > > > > —a > > > > > > > > > > > > I didn’t update classify.api and classify_api.c for the > “Fancy_new_call” yet. In another Pull Request (PR), I’d like to > develop a new plugin that uses the classify entry’s value and write > packet tests etc. > > > > Cheers, > > > > Hemant > > > > From: vpp-dev@lists.fd.io <mailto:vpp-dev@lists.fd.io> <vpp- > d...@lists.fd.io <mailto:vpp-dev@lists.fd.io> > On Behalf Of Andrew > Yourtchenko > Sent: Tuesday, January 19, 2021 2:05 PM > To: hem...@mnkcg.com <mailto:hem...@mnkcg.com> > Cc: vpp-dev@lists.fd.io <mailto:vpp-dev@lists.fd.io> > Subject: Re: [vpp-dev] classifier howto? > > > > Meta-comment: > > > > old_boring_call(foo) { > > /* meat */ > > } > > > > => > > > > Fancy_new_call(foo, bar) { > > /* new meat */ > > } > > > > Old_boring_call(foo) { > > Fancy_new_call(foo, 0); > > } > > > > This way you don’t have to patch umpteen unrelated places. > > --a > > > > > > > > > On 19 Jan 2021, at 19:26, hemant via lists.fd.io > <hemant=mnkcg....@lists.fd.io <mailto:hemant=mnkcg....@lists.fd.io> > > wrote: > > > > Yay, I issued my first code review for VPP using gerrit > for the > issue of this email! > > > > https://gerrit.fd.io/r/c/vpp/+/30844 > > > > The JIRA issue I filed today is at: > https://jira.fd.io/browse/VPP-1967 > > > > Thanks all for replying. > > > > Hemant > > > > From: vpp-dev@lists.fd.io <mailto:vpp-dev@lists.fd.io> > <vpp-dev@lists.fd.io <mailto:vpp-dev@lists.fd.io> > On Behalf Of > hemant via lists.fd.io > Sent: Monday, January 18, 2021 8:41 PM > To: hem...@mnkcg.com <mailto:hem...@mnkcg.com> ; vpp- > d...@lists.fd.io <mailto:vpp-dev@lists.fd.io> > Subject: Re: [vpp-dev] classifier howto? > > > > Please see this PR to fix what I need. > > > > https://github.com/FDio/vpp/pull/33 > > > > Please review – thanks. > > > > Hemant > > > > From: vpp-dev@lists.fd.io <mailto:vpp-dev@lists.fd.io> > <vpp-dev@lists.fd.io <mailto:vpp-dev@lists.fd.io> > On Behalf Of > hemant via lists.fd.io > Sent: Monday, January 18, 2021 10:52 AM > To: vpp-dev@lists.fd.io <mailto:vpp-dev@lists.fd.io> > Subject: [vpp-dev] classifier howto? > > > > I am used to the bihash’s easy to understand key-value > pair API to > program an entry for table lookup using the hash. > > > > > https://github.com/FDio/vpp/blob/master/src/vppinfra/bihash_48_8.h#L > 39 > > > > The value in the struct is a u64. > > > > To see how I program a classifier entry for use by the > data plane, > I looked at the classifier entry data structure: > > > > > https://github.com/FDio/vpp/blob/master/src/vnet/classify/vnet_class > ify.h#L66 > > > > The data structure uses a “u32x4 key[0];” key, but > where is the > value? I am used to seeing a key and value in an entry. > > > > Is “u32 opaque_index” the value? > > If yes, why does bihash use a “u64” for value but the > classifier > uses a u32? > > If the classifier table is hit, my next_node needs the > “value” > associated with the key that incurred the table hit. After all, for > bihash, e.g., clib_bihash_search_48_8() API returns an explicit value. > > > > I plan to use the API in > vnet_classify_add_del_session() to program > ip4 and ip6 src and dst address prefix matching. > > > > Thanks, > > > > Hemant > > > > > > > > > > > > > > > > >
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