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
