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https://issues.apache.org/jira/browse/QPID-3890?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13225130#comment-13225130
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[email protected] commented on QPID-3890:
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The numbers are encouraging! As mentioned below I think this still needs some
work to be safe however.
/trunk/qpid/cpp/src/qpid/broker/Queue.cpp
<https://reviews.apache.org/r/4232/#comment12449>
As it stands, I believe this is unsafe. If you have an empty queue, with a
concurrent consumeNextMessage() from a consumer with a push() from a publisher
then it is possible the consumer does not get a message *and* does not get
notified that there is one.
Moving the listeners.addListener() and the listeners.populate() (from
push()) outside the lock scope means that the consuming thread can fail to get
a message from the allocator, the publishing thread then adds a message and
before the consuming thread adds the consumer to the set of listeners, the
publishing thread populates its set (which will be empty) for notification.
Thus the message remains on the queue without being delivered to an
interested consumer until something else happens to retrigger a notification.
/trunk/qpid/cpp/src/qpid/broker/Queue.cpp
<https://reviews.apache.org/r/4232/#comment12451>
Switching from the consumerLock to messageLock may simplify the code but
obviously won't improve the concurrency. The lock previously used here was
dedicated to protected an entirely distinct set of data. However I would agree
that there is in reality likely to be little gained.
/trunk/qpid/cpp/src/qpid/broker/Queue.cpp
<https://reviews.apache.org/r/4232/#comment12450>
This looks like a subtle change to the logic that is perhaps unintentional?
Previously if ctxt was non null the isEnqueued() test would still be executed
and if false, the method would return. That test is now skipped for the
transactional case.
(If I'm right then a transactional dequeue attempt on a persistent message
that has been removed say due to a ring queue policy limit being reached will
result in a second dequeue attempt on the store that will most likely fail.)
- Gordon
On 2012-03-07 19:23:36, Kenneth Giusti wrote:
bq.
bq. -----------------------------------------------------------
bq. This is an automatically generated e-mail. To reply, visit:
bq. https://reviews.apache.org/r/4232/
bq. -----------------------------------------------------------
bq.
bq. (Updated 2012-03-07 19:23:36)
bq.
bq.
bq. Review request for qpid, Andrew Stitcher, Alan Conway, Gordon Sim, and Ted
Ross.
bq.
bq.
bq. Summary
bq. -------
bq.
bq. In order to improve our parallelism across threads, this patch reduces the
scope over which the Queue's message lock is held.
bq.
bq. I've still got more testing to do, but the simple test cases below show
pretty good performance improvements on my multi-core box. I'd like to get
some early feedback, as there are a lot of little changes to the queue locking
that will need vetting.
bq.
bq. As far as performance is concerned - I've run the following tests on an 8
core Xeon X5550 2.67Ghz box. I used qpid-send and qpid-receive to generate
traffic. All traffic generated in parallel.
bq. All numbers are in messages/second - sorted by best overall throughput.
bq.
bq. Test 1: Funnel Test (shared queue, 2 producers, 1 consumer)
bq.
bq. test setup and execute info:
bq. qpidd --auth no -p 8888 --no-data-dir --worker-threads=3
bq. qpid-config -b $SRC_HOST add queue srcQ1 --max-queue-size=1200000000
--max-queue-count=4000000 --flow-stop-size=0 --flow-stop-count=0
bq. qpid-receive -b $SRC_HOST -a srcQ1 -f -m 4000000 --capacity 2000
--ack-frequency 1000 --print-content no --report-total &
bq. qpid-send -b $SRC_HOST -a srcQ1 -m 2000000 --content-size 300 --capacity
2000 --report-total --sequence no --timestamp no &
bq. qpid-send -b $SRC_HOST -a srcQ1 -m 2000000 --content-size 300 --capacity
2000 --report-total --sequence no --timestamp no &
bq.
bq. trunk: patched:
bq. tp(m/s) tp(m/s)
bq.
bq. S1 :: S2 :: R1 S1 :: S2 :: R1
bq. 73144 :: 72524 :: 112914 91120 :: 83278 :: 133730
bq. 70299 :: 68878 :: 110905 91079 :: 87418 :: 133649
bq. 70002 :: 69882 :: 110241 83957 :: 83600 :: 131617
bq. 70523 :: 68681 :: 108372 83911 :: 82845 :: 128513
bq. 68135 :: 68022 :: 107949 85999 :: 81863 :: 125575
bq.
bq.
bq. Test 2: Quad Client Shared Test (1 queue, 2 senders x 2 Receivers)
bq.
bq. test setup and execute info:
bq. qpidd --auth no -p 8888 --no-data-dir --worker-threads=4
bq. qpid-config -b $SRC_HOST add queue srcQ1 --max-queue-size=1200000000
--max-queue-count=4000000 --flow-stop-size=0 --flow-stop-count=0
bq. qpid-receive -b $SRC_HOST -a srcQ1 -f -m 2000000 --capacity 2000
--ack-frequency 1000 --print-content no --report-total &
bq. qpid-receive -b $SRC_HOST -a srcQ1 -f -m 2000000 --capacity 2000
--ack-frequency 1000 --print-content no --report-total &
bq. qpid-send -b $SRC_HOST -a srcQ1 -m 2000000 --content-size 300 --capacity
2000 --report-total --sequence no --timestamp no &
bq. qpid-send -b $SRC_HOST -a srcQ1 -m 2000000 --content-size 300 --capacity
2000 --report-total --sequence no --timestamp no &
bq.
bq. trunk: patched:
bq. tp(m/s) tp(m/s)
bq.
bq. S1 :: S2 :: R1 :: R2 S1 :: S2 :: R1 :: R2
bq. 52826 :: 52364 :: 52386 :: 52275 64826 :: 64780 :: 64811 :: 64638
bq. 51457 :: 51269 :: 51399 :: 51213 64630 :: 64157 :: 64562 :: 64157
bq. 50557 :: 50432 :: 50468 :: 50366 64023 :: 63832 :: 64092 :: 63748
bq.
bq. **Note: pre-patch, qpidd ran steadily at about 270% cpu during this test.
With the patch, qpidd's cpu utilization was steady at 300%
bq.
bq.
bq. Test 3: Federation Funnel (two federated brokers, 2 producers upstream, 1
consumer downstream)
bq.
bq. test setup and execute info:
bq. qpidd --auth no -p 8888 --no-data-dir --worker-threads=3 -d
bq. qpidd --auth no -p 9999 --no-data-dir --worker-threads=2 -d
bq. qpid-config -b $SRC_HOST add queue srcQ1 --max-queue-size=600000000
--max-queue-count=2000000 --flow-stop-size=0 --flow-stop-count=0
bq. qpid-config -b $SRC_HOST add queue srcQ2 --max-queue-size=600000000
--max-queue-count=2000000 --flow-stop-size=0 --flow-stop-count=0
bq. qpid-config -b $DST_HOST add queue dstQ1 --max-queue-size=1200000000
--max-queue-count=4000000 --flow-stop-size=0 --flow-stop-count=0
bq. qpid-config -b $DST_HOST add exchange fanout dstX1
bq. qpid-config -b $DST_HOST bind dstX1 dstQ1
bq. qpid-route --ack=1000 queue add $DST_HOST $SRC_HOST dstX1 srcQ1
bq. qpid-route --ack=1000 queue add $DST_HOST $SRC_HOST dstX1 srcQ2
bq. qpid-receive -b $DST_HOST -a dstQ1 -f -m 4000000 --capacity 2000
--ack-frequency 1000 --print-content no --report-total &
bq. qpid-send -b $SRC_HOST -a srcQ1 -m 2000000 --content-size 300 --capacity
2000 --report-total --sequence no --timestamp no &
bq. qpid-send -b $SRC_HOST -a srcQ2 -m 2000000 --content-size 300 --capacity
2000 --report-total --sequence no --timestamp no &
bq.
bq.
bq. trunk: patched:
bq. tp(m/s) tp(m/s)
bq.
bq. S1 :: S2 :: R1 S1 :: S2 :: R1
bq. 86150 :: 84146 :: 87665 90877 :: 88534 :: 108418
bq. 89188 :: 88319 :: 82469 87014 :: 86753 :: 107386
bq. 88221 :: 85298 :: 82455 89790 :: 88573 :: 104119
bq.
bq. Still TBD:
bq. - fix message group errors
bq. - verify/fix cluster
bq.
bq.
bq. This addresses bug qpid-3890.
bq. https://issues.apache.org/jira/browse/qpid-3890
bq.
bq.
bq. Diffs
bq. -----
bq.
bq. /trunk/qpid/cpp/src/qpid/broker/Queue.h 1297185
bq. /trunk/qpid/cpp/src/qpid/broker/Queue.cpp 1297185
bq. /trunk/qpid/cpp/src/qpid/broker/QueueListeners.h 1297185
bq. /trunk/qpid/cpp/src/qpid/broker/QueueListeners.cpp 1297185
bq.
bq. Diff: https://reviews.apache.org/r/4232/diff
bq.
bq.
bq. Testing
bq. -------
bq.
bq. unit test (non-cluster)
bq. performance tests as described above.
bq.
bq.
bq. Thanks,
bq.
bq. Kenneth
bq.
bq.
> Improve performance by reducing the use of the Queue's message lock
> -------------------------------------------------------------------
>
> Key: QPID-3890
> URL: https://issues.apache.org/jira/browse/QPID-3890
> Project: Qpid
> Issue Type: Improvement
> Components: C++ Broker
> Affects Versions: 0.16
> Reporter: Ken Giusti
> Assignee: Ken Giusti
> Priority: Minor
> Fix For: Future
>
>
> The mutex that protects the Queue's message container is held longer than it
> really should be (e.g. across statistics updates, etc).
> Reducing the amount of code executed while the lock is held will improve the
> performance of the broker in a multi-process environment.
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