Using the ann-benchmarks framework, I still saw a similar regression as Mayya between 9.3 and 9.4. I investigated and found it was due to "KnnGraphTester to use KnnVectorQuery" ( https://github.com/apache/lucene/pull/796), specifically the change to the warm-up strategy. If I revert it, the results look exactly as expected.
I guess we can keep an eye on the nightly benchmarks tomorrow to double-check there's no drop. It would also be nice to formalize the ann-benchmarks set-up and run it regularly (like we've discussed in https://github.com/apache/lucene/issues/10665). Julie On Mon, Sep 19, 2022 at 10:33 AM Michael Sokolov <msoko...@gmail.com> wrote: > Thanks for your speedy testing! I am observing comparable latencies *when > the index geometry (ie number of segments)* is unchanged. Agree we can > leave this for a later day. I'll proceed to cut 9.4 artifacts > > On Mon, Sep 19, 2022 at 11:02 AM Mayya Sharipova > <mayya.sharip...@elastic.co.invalid> wrote: > >> It would be great if you all are able to test again with >>> https://github.com/apache/lucene/pull/11781/ applied >> >> >> >> I ran the ann benchmarks with this change, and was happy to confirm that >> in my test recall with this PR is the same as in 9.3 branch, although QPS >> is lower, but we can investigate QPSs later. >> >> glove-100-angular M:16 efConstruction:100 >> 9.3 recall9.3 QPSthis PR recallthis PR QPS >> n_cands=10 0.620 2745.933 0.620 1675.500 >> n_cands=20 0.680 2288.665 0.680 1512.744 >> n_cands=40 0.746 1770.243 0.746 1040.240 >> n_cands=80 0.809 1226.738 0.809 695.236 >> n_cands=120 0.843 948.908 0.843 525.914 >> n_cands=200 0.878 671.781 0.878 351.529 >> n_cands=400 0.918 392.265 0.918 207.854 >> n_cands=600 0.937 282.403 0.937 144.311 >> n_cands=800 0.949 214.620 0.949 116.875 >> >> On Sun, Sep 18, 2022 at 6:25 PM Michael Sokolov <msoko...@gmail.com> >> wrote: >> >>> OK, I think I was wrong about latency having increased due to a change >>> in KnnGraphTester -- I did some testing there and couldn't reproduce. >>> There does seem to be a slight vector search latency increase, >>> possibly noise, but maybe due to the branching introduced to check >>> whether to do byte vs float operations? It would be a little >>> surprising if that were the case given the small number of branchings >>> compared to the number of multiplies in dot-product though. >>> >>> On Sun, Sep 18, 2022 at 3:25 PM Michael Sokolov <msoko...@gmail.com> >>> wrote: >>> > >>> > Thanks for the deep-dive Julie. I was able to reproduce the changing >>> > recall. I had introduced some bugs in the diversity checks (that may >>> > have partially canceled each other out? it's hard to understand what >>> > was happening in the buggy case) and posted a fix today >>> > https://github.com/apache/lucene/pull/11781. >>> > >>> > There are a couple of other outstanding issues I found while doing a >>> > bunch of git bisecting; >>> > >>> > I think we might have introduced a (test-only) performance regression >>> > in KnnGraphTester >>> > >>> > We may still be over-allocating the size of NeighborArray, leading to >>> > excessive segmentation? I wonder if we could avoid dynamic >>> > re-allocation there, and simply initialize every neighbor array to >>> > 2*M+1. >>> > >>> > While I don't think these are necessarily blockers, given that we are >>> > releasing HNSW improvements, it seems like we should address these, >>> > especially as the build-graph-on-index is one of the things we are >>> > releasing, and it is (may be?) impacted. I will see if I can put up a >>> > patch or two. >>> > >>> > It would be great if you all are able to test again with >>> > https://github.com/apache/lucene/pull/11781/ applied >>> > >>> > -Mike >>> > >>> > On Fri, Sep 16, 2022 at 11:07 AM Adrien Grand <jpou...@gmail.com> >>> wrote: >>> > > >>> > > Thank you Mike, I just backported the change. >>> > > >>> > > On Thu, Sep 15, 2022 at 6:32 PM Michael Sokolov <msoko...@gmail.com> >>> wrote: >>> > >> >>> > >> it looks like a small bug fix, we have had on main (and 9.x?) for a >>> > >> while now and no test failures showed up, I guess. Should be OK to >>> > >> port. I plan to cut artifacts this weekend, or Monday at the latest, >>> > >> but if you can do the backport today or tomorrow, that's fine by me. >>> > >> >>> > >> On Thu, Sep 15, 2022 at 10:55 AM Adrien Grand <jpou...@gmail.com> >>> wrote: >>> > >> > >>> > >> > Mike, I'm tempted to backport >>> https://github.com/apache/lucene/pull/1068 to branch_9_4, which is a >>> bugfix that looks pretty safe to me. What do you think? >>> > >> > >>> > >> > On Tue, Sep 13, 2022 at 4:11 PM Mayya Sharipova < >>> mayya.sharip...@elastic.co.invalid> wrote: >>> > >> >> >>> > >> >> Thanks for running more tests, Michael. >>> > >> >> It is encouraging that you saw a similar performance between 9.3 >>> and 9.4. I will also run more tests with different parameters. >>> > >> >> >>> > >> >> On Tue, Sep 13, 2022 at 9:30 AM Michael Sokolov < >>> msoko...@gmail.com> wrote: >>> > >> >>> >>> > >> >>> As a follow-up, I ran a test using the same parameters as >>> above, only >>> > >> >>> changing M=200 to M=16. This did result in a single segment in >>> both >>> > >> >>> cases (9.3, 9.4) and the performance was pretty similar; within >>> noise >>> > >> >>> I think. The main difference I saw was that the 9.3 index was >>> written >>> > >> >>> using CFS: >>> > >> >>> >>> > >> >>> 9.4: >>> > >> >>> recall latency nDoc fanout maxConn beamWidth visited >>> index ms >>> > >> >>> 0.755 1.36 1000000 100 16 100 200 891402 >>> 1.00 >>> > >> >>> post-filter >>> > >> >>> -rw-r--r-- 1 sokolovm amazon 382M Sep 13 13:06 >>> > >> >>> _0_Lucene94HnswVectorsFormat_0.vec >>> > >> >>> -rw-r--r-- 1 sokolovm amazon 262K Sep 13 13:06 >>> > >> >>> _0_Lucene94HnswVectorsFormat_0.vem >>> > >> >>> -rw-r--r-- 1 sokolovm amazon 131M Sep 13 13:06 >>> > >> >>> _0_Lucene94HnswVectorsFormat_0.vex >>> > >> >>> >>> > >> >>> 9.3: >>> > >> >>> recall latency nDoc fanout maxConn beamWidth visited >>> index ms >>> > >> >>> 0.775 1.34 1000000 100 16 100 4033 977043 >>> > >> >>> rw-r--r-- 1 sokolovm amazon 297 Sep 13 13:26 _0.cfe >>> > >> >>> -rw-r--r-- 1 sokolovm amazon 516M Sep 13 13:26 _0.cfs >>> > >> >>> -rw-r--r-- 1 sokolovm amazon 340 Sep 13 13:26 _0.si >>> > >> >>> >>> > >> >>> On Tue, Sep 13, 2022 at 8:50 AM Michael Sokolov < >>> msoko...@gmail.com> wrote: >>> > >> >>> > >>> > >> >>> > I ran another test. I thought I had increased the RAM buffer >>> size to >>> > >> >>> > 8G and heap to 16G. However I still see two segments in the >>> index that >>> > >> >>> > was created. And looking at the infostream I see: >>> > >> >>> > >>> > >> >>> > dir=MMapDirectory@ >>> /local/home/sokolovm/workspace/knn-perf/glove-100-angular.hdf5-train-200-200.index >>> > >> >>> > lockFactory=org\ >>> > >> >>> > .apache.lucene.store.NativeFSLockFactory@4466af20 >>> > >> >>> > index= >>> > >> >>> > version=9.4.0 >>> > >> >>> > analyzer=org.apache.lucene.analysis.standard.StandardAnalyzer >>> > >> >>> > ramBufferSizeMB=8000.0 >>> > >> >>> > maxBufferedDocs=-1 >>> > >> >>> > ... >>> > >> >>> > perThreadHardLimitMB=1945 >>> > >> >>> > ... >>> > >> >>> > DWPT 0 [2022-09-13T02:42:53.329404950Z; main]: flush postings >>> as >>> > >> >>> > segment _6 numDocs=555373 >>> > >> >>> > IW 0 [2022-09-13T02:42:53.330671171Z; main]: 0 msec to write >>> norms >>> > >> >>> > IW 0 [2022-09-13T02:42:53.331113184Z; main]: 0 msec to write >>> docValues >>> > >> >>> > IW 0 [2022-09-13T02:42:53.331320146Z; main]: 0 msec to write >>> points >>> > >> >>> > IW 0 [2022-09-13T02:42:56.424195657Z; main]: 3092 msec to >>> write vectors >>> > >> >>> > IW 0 [2022-09-13T02:42:56.429239944Z; main]: 4 msec to finish >>> stored fields >>> > >> >>> > IW 0 [2022-09-13T02:42:56.429593512Z; main]: 0 msec to write >>> postings >>> > >> >>> > and finish vectors >>> > >> >>> > IW 0 [2022-09-13T02:42:56.430309031Z; main]: 0 msec to write >>> fieldInfos >>> > >> >>> > DWPT 0 [2022-09-13T02:42:56.431721622Z; main]: new segment >>> has 0 deleted docs >>> > >> >>> > DWPT 0 [2022-09-13T02:42:56.431921144Z; main]: new segment >>> has 0 >>> > >> >>> > soft-deleted docs >>> > >> >>> > DWPT 0 [2022-09-13T02:42:56.435738086Z; main]: new segment >>> has no >>> > >> >>> > vectors; no norms; no docValues; no prox; freqs >>> > >> >>> > DWPT 0 [2022-09-13T02:42:56.435952356Z; main]: >>> > >> >>> > flushedFiles=[_6_Lucene94HnswVectorsFormat_0.vec, _6.fdm, >>> _6.fdt, _6_\ >>> > >> >>> > Lucene94HnswVectorsFormat_0.vem, _6.fnm, _6.fdx, >>> > >> >>> > _6_Lucene94HnswVectorsFormat_0.vex] >>> > >> >>> > DWPT 0 [2022-09-13T02:42:56.436121861Z; main]: flushed >>> codec=Lucene94 >>> > >> >>> > DWPT 0 [2022-09-13T02:42:56.437691468Z; main]: flushed: >>> segment=_6 >>> > >> >>> > ramUsed=1,945.002 MB newFlushedSize=1,065.701 MB \ >>> > >> >>> > docs/MB=521.134 >>> > >> >>> > >>> > >> >>> > so I think it's this perThreadHardLimit that is triggering the >>> > >> >>> > flushes? TBH this isn't something I had seen before; but the >>> docs say: >>> > >> >>> > >>> > >> >>> > /** >>> > >> >>> > * Expert: Sets the maximum memory consumption per thread >>> triggering >>> > >> >>> > a forced flush if exceeded. A >>> > >> >>> > * {@link DocumentsWriterPerThread} is forcefully flushed >>> once it >>> > >> >>> > exceeds this limit even if the >>> > >> >>> > * {@link #getRAMBufferSizeMB()} has not been exceeded. >>> This is a >>> > >> >>> > safety limit to prevent a {@link >>> > >> >>> > * DocumentsWriterPerThread} from address space exhaustion >>> due to >>> > >> >>> > its internal 32 bit signed >>> > >> >>> > * integer based memory addressing. The given value must be >>> less >>> > >> >>> > that 2GB (2048MB) >>> > >> >>> > * >>> > >> >>> > * @see #DEFAULT_RAM_PER_THREAD_HARD_LIMIT_MB >>> > >> >>> > */ >>> > >> >>> > >>> > >> >>> > On Mon, Sep 12, 2022 at 6:28 PM Michael Sokolov < >>> msoko...@gmail.com> wrote: >>> > >> >>> > > >>> > >> >>> > > Hi Mayya, thanks for persisting - I think we need to >>> wrestle this to >>> > >> >>> > > the ground for sure. In the test I ran, RAM buffer was the >>> default >>> > >> >>> > > checked in, which is weirdly: 1994MB. I did not >>> specifically set heap >>> > >> >>> > > size. I used maxConn/M=200. I'll try with larger buffer to >>> see if I >>> > >> >>> > > can get 9.4 to produce a single segment for the same test >>> settings. I >>> > >> >>> > > see you used a much smaller M (16), which should have >>> produced quite >>> > >> >>> > > small graphs, and I agree, should have been a single >>> segment. Were you >>> > >> >>> > > able to verify the number of segments? >>> > >> >>> > > >>> > >> >>> > > Agree that decrease in recall is not expected when more >>> segments are produced. >>> > >> >>> > > >>> > >> >>> > > On Mon, Sep 12, 2022 at 1:51 PM Mayya Sharipova >>> > >> >>> > > <mayya.sharip...@elastic.co.invalid> wrote: >>> > >> >>> > > > >>> > >> >>> > > > Hello Michael, >>> > >> >>> > > > Thanks for checking. >>> > >> >>> > > > Sorry for bringing this up again. >>> > >> >>> > > > First of all, I am ok with proceeding with the Lucene 9.4 >>> release and leaving the performance investigations for later. >>> > >> >>> > > > >>> > >> >>> > > > I am interested in what's the maxConn/M value you used >>> for your tests? What was the heap memory and the size of the RAM buffer for >>> indexing? >>> > >> >>> > > > Usually, when we have multiple segments, recall should >>> increase, not decrease. But I agree that with multiple segments we can see >>> a big drop in QPS. >>> > >> >>> > > > >>> > >> >>> > > > Here is my investigation with detailed output of the >>> performance difference between 9.3 and 9.4 releases. In my tests I used a >>> large indexing buffer (2Gb) and large heap (5Gb) to end up with a single >>> segment for both 9.3 and 9.4 tests, but still see a big drop in QPS in 9.4. >>> > >> >>> > > > >>> > >> >>> > > > Thank you. >>> > >> >>> > > > >>> > >> >>> > > > >>> > >> >>> > > > >>> > >> >>> > > > >>> > >> >>> > > > >>> > >> >>> > > > On Fri, Sep 9, 2022 at 12:21 PM Alan Woodward < >>> romseyg...@gmail.com> wrote: >>> > >> >>> > > >> >>> > >> >>> > > >> Done. Thanks! >>> > >> >>> > > >> >>> > >> >>> > > >> > On 9 Sep 2022, at 16:32, Michael Sokolov < >>> msoko...@gmail.com> wrote: >>> > >> >>> > > >> > >>> > >> >>> > > >> > Hi Alan - I checked out the interval queries patch; >>> seems pretty safe, >>> > >> >>> > > >> > please go ahead and port to 9.4. Thanks! >>> > >> >>> > > >> > >>> > >> >>> > > >> > Mike >>> > >> >>> > > >> > >>> > >> >>> > > >> > On Fri, Sep 9, 2022 at 10:41 AM Alan Woodward < >>> romseyg...@gmail.com> wrote: >>> > >> >>> > > >> >> >>> > >> >>> > > >> >> Hi Mike, >>> > >> >>> > > >> >> >>> > >> >>> > > >> >> I’ve opened >>> https://github.com/apache/lucene/pull/11760 as a small bug fix PR for a >>> problem with interval queries. Am I OK to port this to the 9.4 branch? >>> > >> >>> > > >> >> >>> > >> >>> > > >> >> Thanks, Alan >>> > >> >>> > > >> >> >>> > >> >>> > > >> >> On 2 Sep 2022, at 20:42, Michael Sokolov < >>> msoko...@gmail.com> wrote: >>> > >> >>> > > >> >> >>> > >> >>> > > >> >> NOTICE: >>> > >> >>> > > >> >> >>> > >> >>> > > >> >> Branch branch_9_4 has been cut and versions updated >>> to 9.5 on stable branch. >>> > >> >>> > > >> >> >>> > >> >>> > > >> >> Please observe the normal rules: >>> > >> >>> > > >> >> >>> > >> >>> > > >> >> * No new features may be committed to the branch. >>> > >> >>> > > >> >> * Documentation patches, build patches and serious >>> bug fixes may be >>> > >> >>> > > >> >> committed to the branch. However, you should submit >>> all patches you >>> > >> >>> > > >> >> want to commit to Jira first to give others the >>> chance to review >>> > >> >>> > > >> >> and possibly vote against the patch. Keep in mind >>> that it is our >>> > >> >>> > > >> >> main intention to keep the branch as stable as >>> possible. >>> > >> >>> > > >> >> * All patches that are intended for the branch should >>> first be committed >>> > >> >>> > > >> >> to the unstable branch, merged into the stable >>> branch, and then into >>> > >> >>> > > >> >> the current release branch. >>> > >> >>> > > >> >> * Normal unstable and stable branch development may >>> continue as usual. >>> > >> >>> > > >> >> However, if you plan to commit a big change to the >>> unstable branch >>> > >> >>> > > >> >> while the branch feature freeze is in effect, think >>> twice: can't the >>> > >> >>> > > >> >> addition wait a couple more days? Merges of bug fixes >>> into the branch >>> > >> >>> > > >> >> may become more difficult. >>> > >> >>> > > >> >> * Only Jira issues with Fix version 9.4 and priority >>> "Blocker" will delay >>> > >> >>> > > >> >> a release candidate build. >>> > >> >>> > > >> >> >>> > >> >>> > > >> >> >>> --------------------------------------------------------------------- >>> > >> >>> > > >> >> To unsubscribe, e-mail: >>> dev-unsubscr...@lucene.apache.org >>> > >> >>> > > >> >> For additional commands, e-mail: >>> dev-h...@lucene.apache.org >>> > >> >>> > > >> >> >>> > >> >>> > > >> >> >>> > >> >>> > > >> > >>> > >> >>> > > >> > >>> --------------------------------------------------------------------- >>> > >> >>> > > >> > To unsubscribe, e-mail: >>> dev-unsubscr...@lucene.apache.org >>> > >> >>> > > >> > For additional commands, e-mail: >>> dev-h...@lucene.apache.org >>> > >> >>> > > >> > >>> > >> >>> > > >> >>> > >> >>> > > >> >>> > >> >>> > > >> >>> --------------------------------------------------------------------- >>> > >> >>> > > >> To unsubscribe, e-mail: >>> dev-unsubscr...@lucene.apache.org >>> > >> >>> > > >> For additional commands, e-mail: >>> dev-h...@lucene.apache.org >>> > >> >>> > > >> >>> > >> >>> >>> > >> >>> >>> --------------------------------------------------------------------- >>> > >> >>> To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org >>> > >> >>> For additional commands, e-mail: dev-h...@lucene.apache.org >>> > >> >>> >>> > >> > >>> > >> > >>> > >> > -- >>> > >> > Adrien >>> > >> >>> > >> >>> --------------------------------------------------------------------- >>> > >> To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org >>> > >> For additional commands, e-mail: dev-h...@lucene.apache.org >>> > >> >>> > > >>> > > >>> > > -- >>> > > Adrien >>> >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org >>> For additional commands, e-mail: dev-h...@lucene.apache.org >>> >>>