> On 2012-03-07 21:30:28, Andrew Stitcher wrote: > > This is great work. > > > > The most important thing on my mind though is how do ensure that work like > > this maintains correctness? > > > > Do we have some rules/guidelines for the use of the Queue structs that we > > can use to inspect the code to satisfy its correctness? A simple rule like > > this would be "take the blah lock before capturing or changing the foo > > state". It looks like we might have had rules like that, but these changes > > are so broad it's difficult for me to inspect the code and reconstruct what > > rules now apply (if any). > > > > On another point - I see you've added the use of a RWLock - it's always > > good to benchmark with a plain mutex before using one of these as they are > > generally higher overhead and unless the use is "read lock mostly write > > lock seldom" plain mutexes can win. > > Kenneth Giusti wrote: > Re: locking rules - good point Andrew. Most (all?) of these changes I > made simply by manually reviewing the existing code's locking behavior, and > trying to identify what can be safely moved outside the locks. I'll update > this patch with comments that explicitly call out those data members & > actions that must hold the lock. > > The RWLock - hmm.. that may be an unintentional change: at first I had a > separate lock for the queue observer container which was rarely written too. > I abandoned that change and put the queue observers under the queue lock > since otherwise the order of events (as seen by the observers) could be > re-arranged. > > Kenneth Giusti wrote: > Doh - sorry, replied with way too low Caffiene/Blood ratio. You're > referring to the lock in the listener - yes. Gordon points out that this may > be unsafe, so I need to think about it a bit more.
The order of events as seen by observers can be re-arranged with the patch as it stands (at least those for acquires and dequeues, enqueues would still be ordered correctly wrt each other). Regarding the listeners access, I think you could fix it by e.g. having an atomic counter that was incremented after pushing the message but before populating notification set, checking that count before trying to acquire the message on the consume side and then rechecking it before adding the consumer to listeners if there was no message. If the number changes between the last two checks you would retry the acquisition. - Gordon ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4232/#review5691 ----------------------------------------------------------- On 2012-03-07 19:23:36, Kenneth Giusti wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/4232/ > ----------------------------------------------------------- > > (Updated 2012-03-07 19:23:36) > > > Review request for qpid, Andrew Stitcher, Alan Conway, Gordon Sim, and Ted > Ross. > > > Summary > ------- > > In order to improve our parallelism across threads, this patch reduces the > scope over which the Queue's message lock is held. > > 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. > > 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. > All numbers are in messages/second - sorted by best overall throughput. > > Test 1: Funnel Test (shared queue, 2 producers, 1 consumer) > > test setup and execute info: > qpidd --auth no -p 8888 --no-data-dir --worker-threads=3 > qpid-config -b $SRC_HOST add queue srcQ1 --max-queue-size=1200000000 > --max-queue-count=4000000 --flow-stop-size=0 --flow-stop-count=0 > qpid-receive -b $SRC_HOST -a srcQ1 -f -m 4000000 --capacity 2000 > --ack-frequency 1000 --print-content no --report-total & > qpid-send -b $SRC_HOST -a srcQ1 -m 2000000 --content-size 300 --capacity 2000 > --report-total --sequence no --timestamp no & > qpid-send -b $SRC_HOST -a srcQ1 -m 2000000 --content-size 300 --capacity 2000 > --report-total --sequence no --timestamp no & > > trunk: patched: > tp(m/s) tp(m/s) > > S1 :: S2 :: R1 S1 :: S2 :: R1 > 73144 :: 72524 :: 112914 91120 :: 83278 :: 133730 > 70299 :: 68878 :: 110905 91079 :: 87418 :: 133649 > 70002 :: 69882 :: 110241 83957 :: 83600 :: 131617 > 70523 :: 68681 :: 108372 83911 :: 82845 :: 128513 > 68135 :: 68022 :: 107949 85999 :: 81863 :: 125575 > > > Test 2: Quad Client Shared Test (1 queue, 2 senders x 2 Receivers) > > test setup and execute info: > qpidd --auth no -p 8888 --no-data-dir --worker-threads=4 > qpid-config -b $SRC_HOST add queue srcQ1 --max-queue-size=1200000000 > --max-queue-count=4000000 --flow-stop-size=0 --flow-stop-count=0 > qpid-receive -b $SRC_HOST -a srcQ1 -f -m 2000000 --capacity 2000 > --ack-frequency 1000 --print-content no --report-total & > qpid-receive -b $SRC_HOST -a srcQ1 -f -m 2000000 --capacity 2000 > --ack-frequency 1000 --print-content no --report-total & > qpid-send -b $SRC_HOST -a srcQ1 -m 2000000 --content-size 300 --capacity 2000 > --report-total --sequence no --timestamp no & > qpid-send -b $SRC_HOST -a srcQ1 -m 2000000 --content-size 300 --capacity 2000 > --report-total --sequence no --timestamp no & > > trunk: patched: > tp(m/s) tp(m/s) > > S1 :: S2 :: R1 :: R2 S1 :: S2 :: R1 :: R2 > 52826 :: 52364 :: 52386 :: 52275 64826 :: 64780 :: 64811 :: 64638 > 51457 :: 51269 :: 51399 :: 51213 64630 :: 64157 :: 64562 :: 64157 > 50557 :: 50432 :: 50468 :: 50366 64023 :: 63832 :: 64092 :: 63748 > > **Note: pre-patch, qpidd ran steadily at about 270% cpu during this test. > With the patch, qpidd's cpu utilization was steady at 300% > > > Test 3: Federation Funnel (two federated brokers, 2 producers upstream, 1 > consumer downstream) > > test setup and execute info: > qpidd --auth no -p 8888 --no-data-dir --worker-threads=3 -d > qpidd --auth no -p 9999 --no-data-dir --worker-threads=2 -d > qpid-config -b $SRC_HOST add queue srcQ1 --max-queue-size=600000000 > --max-queue-count=2000000 --flow-stop-size=0 --flow-stop-count=0 > qpid-config -b $SRC_HOST add queue srcQ2 --max-queue-size=600000000 > --max-queue-count=2000000 --flow-stop-size=0 --flow-stop-count=0 > qpid-config -b $DST_HOST add queue dstQ1 --max-queue-size=1200000000 > --max-queue-count=4000000 --flow-stop-size=0 --flow-stop-count=0 > qpid-config -b $DST_HOST add exchange fanout dstX1 > qpid-config -b $DST_HOST bind dstX1 dstQ1 > qpid-route --ack=1000 queue add $DST_HOST $SRC_HOST dstX1 srcQ1 > qpid-route --ack=1000 queue add $DST_HOST $SRC_HOST dstX1 srcQ2 > qpid-receive -b $DST_HOST -a dstQ1 -f -m 4000000 --capacity 2000 > --ack-frequency 1000 --print-content no --report-total & > qpid-send -b $SRC_HOST -a srcQ1 -m 2000000 --content-size 300 --capacity 2000 > --report-total --sequence no --timestamp no & > qpid-send -b $SRC_HOST -a srcQ2 -m 2000000 --content-size 300 --capacity 2000 > --report-total --sequence no --timestamp no & > > > trunk: patched: > tp(m/s) tp(m/s) > > S1 :: S2 :: R1 S1 :: S2 :: R1 > 86150 :: 84146 :: 87665 90877 :: 88534 :: 108418 > 89188 :: 88319 :: 82469 87014 :: 86753 :: 107386 > 88221 :: 85298 :: 82455 89790 :: 88573 :: 104119 > > Still TBD: > - fix message group errors > - verify/fix cluster > > > This addresses bug qpid-3890. > https://issues.apache.org/jira/browse/qpid-3890 > > > Diffs > ----- > > /trunk/qpid/cpp/src/qpid/broker/Queue.h 1297185 > /trunk/qpid/cpp/src/qpid/broker/Queue.cpp 1297185 > /trunk/qpid/cpp/src/qpid/broker/QueueListeners.h 1297185 > /trunk/qpid/cpp/src/qpid/broker/QueueListeners.cpp 1297185 > > Diff: https://reviews.apache.org/r/4232/diff > > > Testing > ------- > > unit test (non-cluster) > performance tests as described above. > > > Thanks, > > Kenneth > >
