2017-07-11 11:04 GMT+02:00 Sijie Guo <[email protected]>: > I think Netty4 requires more offheap memory. you might need to tune the JVM > settings. I doubt that latency diff coming from the JVM gc. > > A simple thing to verify that is to dump the gc log by adding " -Xloggc:" > setting and compare the gc logs between versions. >
Enabling G1 GC (-XX:+UseG1GC) apparently solves the difference between 4.4 and 4.5. And I a loop the bench (in order to have a warm JVM) numbers become more stable and similar to each other I have the "other issue" pending, the fact that latency (time for asynchAddEntry to complete) is really bad and unpredictable (from 100 ms to 2000ms) and if I introduce a Thread.sleep(1) all the callbacks complete always with success in < 10ms. This happens even with G1 GC. Without the "sleep(1)" my machine uses a lot of CPU (I have 8 "CPUs") and with the "sleep(1)" the load is slightly lower Honestly for me this is still a problem and I hope that with your help I will be able to find the problem, wherever it is (in BK code or in the way I am doing the bench) I will try to create a new more complete bench -- Enrico > > - Sijie > > On Tue, Jul 11, 2017 at 12:16 AM, Enrico Olivelli <[email protected]> > wrote: > > > a did a bisect and the culprit (in my opinion) is the switch to netty 4 > for > > the performance regression from 4.5 and 4.4 > > > > at commit: > > commit 811ece53a1c975c4e768422f3d622ac9de6b3e41 BOOKKEEPER-1058: > Ignore > > already deleted ledger on replication audit > > > > Total time: 204 ms > > Total real time: 79 ms per entry > > > > at commit: > > commit 74f795136c1fff3badb29fc982d0cc2d43096b45 BOOKKEEPER-1008: Netty > 4.1 > > > > Total time: 308 ms > > Total real time: 189 ms per entry > > > > I have tried with epoll and with local transport, results does not > change. > > I tried to upgrade to netty 4.1.13 too, but no change > > > > Could it be the memory allocator of netty which is overwhelmed with > sudden > > bursts of allocation ? > > I did some trial with UnpooledByteBufAllocator.DEFAULT and it helps a > > little, we get to "110 ms per entry" vs "189 ms per entry" > > > > the bench is here: > > https://github.com/eolivelli/bookkeepers-benchs/blob/ > master/src/test/java/ > > BookKeeperWriteTest.java > > > > > > -- Enrico > > > > > > > > 2017-07-10 19:46 GMT+02:00 Enrico Olivelli <[email protected]>: > > > > > > > > > > > Il lun 10 lug 2017, 18:21 Venkateswara Rao Jujjuri <[email protected]> > > ha > > > scritto: > > > > > >> With Netty changes, lack of native epoll() has huge perf impact as per > > >> Kishore. > > >> Are you sure you are using epoll()? > > >> > > > > > > Yes. I tried with netty local transport too. It seems not related to > > netty > > > to me. > > > I will double check, tomorrow > > > Enrico > > > > > > > > >> On Mon, Jul 10, 2017 at 1:49 AM, Enrico Olivelli <[email protected] > > > > >> wrote: > > >> > > >> > 2017-07-10 10:40 GMT+02:00 Sijie Guo <[email protected]>: > > >> > > > >> > > Also one other thing to check is the JVM settings. Do you mind > > sharing > > >> > that > > >> > > as well? > > >> > > > > >> > > > > >> > this is the surefire config, I am using oracle jdk 8 > > >> > > > >> > <plugin> > > >> > <artifactId>maven-surefire-plugin</artifactId> > > >> > <version>2.20</version> > > >> > <configuration> > > >> > <forkCount>1</forkCount> > > >> > <reuseForks>false</reuseForks> > > >> > > > >> > <forkedProcessTimeoutInSeconds>300</forkedProcessTimeoutInSeconds> > > >> > <argLine>-Xmx2G > > >> > -Djava.io.tmpdir=${basedir}/target</argLine> > > >> > </configuration> > > >> > </plugin> > > >> > > > >> > -- Enrico > > >> > > > >> > > > >> > > > >> > > Sijie > > >> > > > > >> > > On Jul 10, 2017 1:17 AM, "Sijie Guo" <[email protected]> wrote: > > >> > > > > >> > > > I am not sure if there is any default values changed for journal > > >> > > settings. > > >> > > > I would suggest you testing by setting specifically the journal > > >> > settings. > > >> > > > > > >> > > > Also if you can share your benchmark, that would be good for > other > > >> > people > > >> > > > to verify. > > >> > > > > > >> > > > Sijie > > >> > > > > > >> > > > On Jul 10, 2017 12:32 AM, "Enrico Olivelli" < > [email protected]> > > >> > wrote: > > >> > > > > > >> > > >> Hi, > > >> > > >> I am doing some benchmarks on BK, I see that from 4.4.0 to > 4.5.0 > > >> there > > >> > > is > > >> > > >> something "slow" but I cannot understand what. I really hope > that > > >> I am > > >> > > >> wrong. > > >> > > >> > > >> > > >> I am working with writes, I will pass to reads once writes will > > be > > >> ok. > > >> > > >> My problem is both on latency (time for AddComplete callback to > > >> > > complete) > > >> > > >> and on overall throuput. > > >> > > >> > > >> > > >> Actually I have two distinct problems, but working on the first > > >> > problem > > >> > > I > > >> > > >> found a performance regression. > > >> > > >> I know that talking about "slow" things it is an hard matter, > so > > I > > >> > will > > >> > > >> try > > >> > > >> do describe as much as possible all the aspects that I think > are > > >> > > relevant. > > >> > > >> > > >> > > >> First problem: under certain load performance > > (latency+throughput) > > >> > > degrade > > >> > > >> too much > > >> > > >> Second problem: the first problem is more evident in 4.5.0 > > >> > > >> > > >> > > >> Let's describe my testcase and why I am worried. > > >> > > >> The bench issues a batch of asyncAddEntry and prints the > average > > >> time > > >> > > for > > >> > > >> AddComplete to complete and the overall clock time. > > >> > > >> > > >> > > >> This is the code > > >> > > >> > > >> > > >> private static final byte[] TEST_DATA = new byte[35 * 1024]; > > >> > > >> private static final int testsize = 1000; > > >> > > >> > > >> > > >> ...... (start 1 bookie, see below) > > >> > > >> ClientConfiguration clientConfiguration = new > > >> > > >> ClientConfiguration(); > > >> > > >> clientConfiguration.setZkServers(env.getAddress()) > ; > > >> > > >> try (BookKeeper bk = new BookKeeper( > > >> clientConfiguration); > > >> > > >> LedgerHandle lh = bk.createLedger(1, 1, 1, > > >> > > >> BookKeeper.DigestType.CRC32, new byte[0])) { > > >> > > >> LongAdder totalTime = new LongAdder(); > > >> > > >> long _start = System.currentTimeMillis(); > > >> > > >> Collection<CompletableFuture> batch = new > > >> > > >> ConcurrentLinkedQueue<>(); > > >> > > >> for (int i = 0; i < testsize; i++) { > > >> > > >> CompletableFuture cf = new > > CompletableFuture(); > > >> > > >> batch.add(cf); > > >> > > >> lh.asyncAddEntry(TEST_DATA, new > > >> > > >> AsyncCallback.AddCallback() { > > >> > > >> > > >> > > >> long start = > System.currentTimeMillis(); > > >> > > >> > > >> > > >> @Override > > >> > > >> public void addComplete(int rc, > > >> LedgerHandle > > >> > lh, > > >> > > >> long entryId, Object ctx) { > > >> > > >> long now = > > >> > > >> System.currentTimeMillis(); > > >> > > >> CompletableFuture _cf = > > >> > (CompletableFuture) > > >> > > >> ctx; > > >> > > >> if (rc == BKException.Code.OK) { > > >> > > >> _cf.complete(""); > > >> > > >> } else { > > >> > > >> > > >> > > >> _cf.completeExceptionally(BKException.create(rc)); > > >> > > >> } > > >> > > >> totalTime.add(now - start); > > >> > > >> } > > >> > > >> }, cf); > > >> > > >> // Thread.sleep(1); // this is the > > >> tirgger!!! > > >> > > >> } > > >> > > >> assertEquals(testsize, batch.size()); > > >> > > >> for (CompletableFuture f : batch) { > > >> > > >> f.get(); > > >> > > >> } > > >> > > >> long _stop = System.currentTimeMillis(); > > >> > > >> long delta = _stop - _start; > > >> > > >> System.out.println("Total time: " + delta + " > > ms"); > > >> > > >> System.out.println("Total real time: " + > > >> > > totalTime.sum() + > > >> > > >> " ms -> "+(totalTime.sum()/testsize)+" ms per entry"); > > >> > > >> } > > >> > > >> > > >> > > >> Bookie config: > > >> > > >> ServerConfiguration conf = new ServerConfiguration(); > > >> > > >> conf.setBookiePort(5621); > > >> > > >> conf.setUseHostNameAsBookieID(true); > > >> > > >> > > >> > > >> Path targetDir = path.resolve("bookie_data"); > > >> > > >> conf.setZkServers("localhost:1282"); > > >> > > >> conf.setLedgerDirNames(new > > >> > > >> String[]{targetDir.toAbsolutePath().toString()}); > > >> > > >> conf.setJournalDirName(targetDir.toAbsolutePath(). > > >> > toString()); > > >> > > >> conf.setFlushInterval(1000); > > >> > > >> conf.setJournalFlushWhenQueueEmpty(true); > > >> > > >> conf.setProperty("journalMaxGroupWaitMSec", 0); > > >> > > >> conf.setProperty("journalBufferedWritesThreshold", > > 1024); > > >> > > >> conf.setAutoRecoveryDaemonEnabled(false); > > >> > > >> conf.setEnableLocalTransport(true); > > >> > > >> conf.setAllowLoopback(true); > > >> > > >> > > >> > > >> The tests starts one ZK server + 1 Bookie + the testcase in a > > JUnit > > >> > test > > >> > > >> > > >> > > >> > > >> > > >> Results: > > >> > > >> A - BK-4.4.0: > > >> > > >> Total time: 209 ms > > >> > > >> Total real time: 194337 ms -> 194 ms per entry > > >> > > >> > > >> > > >> B - BK-4.5.0-SNAPSHOT: > > >> > > >> Total time: 269 ms > > >> > > >> Total real time: 239918 ms -> 239 ms per entry > > >> > > >> > > >> > > >> C - BK-4.4,0 with sleep(1): > > >> > > >> Total time: 1113 ms (1000 ms sleep time) > > >> > > >> Total real time: 4238 ms -> 4 ms per entry > > >> > > >> > > >> > > >> D - BK-4.5,0-SNAPSHOT with sleep(1): > > >> > > >> Total time: 1121 ms (1000 ms sleep time) > > >> > > >> Total real time: 8018 ms -> 8 ms per entry > > >> > > >> > > >> > > >> Problem 1 (unexpected performance degradation): > > >> > > >> Times per entry (latency) are incredibly slow in cases A and B. > > >> > > >> If I add a sleep(1) between one call of asyncAddEntry and the > > next > > >> > > >> "latency" is around 4 ms per entry. > > >> > > >> > > >> > > >> Problem 2: worse performance on 4.5.0 > > >> > > >> Compare A vs B and C vs D, it is self-explaining. > > >> > > >> > > >> > > >> I am running the test on my laptop, with linux 64bit (Fedora), > 12 > > >> GB > > >> > > RAM, > > >> > > >> no swap, on an SSD disk. The results are similar on other > > >> computers. > > >> > > >> > > >> > > >> It seems that if I issue too many addEntry the systems slows > > down. > > >> > > >> > > >> > > >> Please note this fact: > > >> > > >> numbers for case A and B (without sleep) mean that all the adds > > got > > >> > > >> completed almost together > > >> > > >> > > >> > > >> for the 4.5 vs 4.4 case: > > >> > > >> I tried to disable all of the threadpool enhancements > (different > > >> > > >> read/write > > >> > > >> pools)....it makes not difference > > >> > > >> > > >> > > >> Questions: > > >> > > >> > > >> > > >> Is the "grouping" logic of the journal ? > > >> > > >> > > >> > > >> Is there a way of making a burst of 1000 async writes on the > same > > >> > ledger > > >> > > >> perform <10 ms latency ? (in my real case I have bursts of > > >> concurrent > > >> > > >> writes from different threads) > > >> > > >> > > >> > > >> Why 4.5.0 is anyway slower ? > > >> > > >> > > >> > > >> Thanks > > >> > > >> > > >> > > >> -- Enrico > > >> > > >> > > >> > > > > > >> > > > > >> > > > >> > > >> > > >> > > >> -- > > >> Jvrao > > >> --- > > >> First they ignore you, then they laugh at you, then they fight you, > then > > >> you win. - Mahatma Gandhi > > >> > > > -- > > > > > > > > > -- Enrico Olivelli > > > > > >
