f43c007605
3 Commits
| Author | SHA1 | Message | Date | |
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Emilio G. Cota
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977ec47de0 |
qht-bench: relax test_start/stop atomic accesses
test_start/stop are used only as flags to loop on. Barriers are unnecessary, since no dependent data is transferred among threads apart from the flags themselves. This commit relaxes the three accesses to test_start/stop that were not yet relaxed. Signed-off-by: Emilio G. Cota <cota@braap.org> |
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Paolo Bonzini
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e9abfcb57f |
clean-includes: run it once more
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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Emilio G. Cota
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515864a0d7 |
qht: add qht-bench, a performance benchmark
This serves as a performance benchmark as well as a stress test for QHT. We can tweak quite a number of things, including the number of resize threads and how frequently resizes are triggered. A performance comparison of QHT vs CLHT[1] and ck_hs[2] using this same benchmark program can be found here: http://imgur.com/a/0Bms4 The tests are run on a 64-core AMD Opteron 6376, pinning threads to cores favoring same-socket cores. For each run, qht-bench is invoked with: $ tests/qht-bench -d $duration -n $n -u $u -g $range , where $duration is in seconds, $n is the number of threads, $u is the update rate (0.0 to 100.0), and $range is the number of keys. Note that ck_hs's performance drops significantly as writes go up, since it requires an external lock (I used a ck_spinlock) around every write. Also, note that CLHT instead of using a seqlock, relies on an allocator that does not ever return the same address during the same read-critical section. This gives it a slight performance advantage over QHT on read-heavy workloads, since the seqlock writes aren't there. [1] CLHT: https://github.com/LPD-EPFL/CLHT https://infoscience.epfl.ch/record/207109/files/ascy_asplos15.pdf [2] ck_hs: http://concurrencykit.org/ http://backtrace.io/blog/blog/2015/03/13/workload-specialization/ A few of those plots are shown in text here, since that site might not be online forever. Throughput is on Mops/s on the Y axis. 200K keys, 0 % updates 450 ++--+------+------+-------+-------+-------+-------+------+-------+--++ | + + + + + + + + +N+ | 400 ++ ---+E+ ++ | +++---- | 350 ++ 9 ++------+------++ --+E+ -+H+ ++ | | +H+- | -+N+---- ---- +++ | 300 ++ 8 ++ +E+ ++ -----+E+ --+H+ ++ | | +++ | -+N+-----+H+-- | 250 ++ 7 ++------+------++ +++-----+E+---- ++ 200 ++ 1 -+E+-----+H+ ++ | ---- qht +-E--+ | 150 ++ -+E+ clht +-H--+ ++ | ---- ck +-N--+ | 100 ++ +E+ ++ | ---- | 50 ++ -+E+ ++ | +E+E+ + + + + + + + + | 0 ++--E------+------+-------+-------+-------+-------+------+-------+--++ 1 8 16 24 32 40 48 56 64 Number of threads 200K keys, 1 % updates 350 ++--+------+------+-------+-------+-------+-------+------+-------+--++ | + + + + + + + + -+E+ | 300 ++ -----+H+ ++ | +E+-- | | 9 ++------+------++ +++---- | 250 ++ | +E+ -- | -+E+ ++ | 8 ++ -- ++ ---- | 200 ++ | +++- | +++ ---+E+ ++ | 7 ++------N------++ -+E+-- qht +-E--+ | | 1 +++---- clht +-H--+ | 150 ++ -+E+ ck +-N--+ ++ | ---- | 100 ++ +E+ ++ | ---- | | -+E+ | 50 ++ +H+-+N+----+N+-----+N+------ ++ | +E+E+ + + + +N+-----+N+-----+N+----+N+-----+N+ | 0 ++--E------+------+-------+-------+-------+-------+------+-------+--++ 1 8 16 24 32 40 48 56 64 Number of threads 200K keys, 20 % updates 300 ++--+------+------+-------+-------+-------+-------+------+-------+--++ | + + + + + + + + + | | -+H+ | 250 ++ ---- ++ | 9 ++------+------++ --+H+ ---+E+ | | 8 ++ +H+-- ++ -+H+----+E+-- | 200 ++ | +E+ --| -----+E+-- +++ ++ | 7 ++ + ---- ++ ---+H+---- +++ qht +-E--+ | 150 ++ 6 ++------N------++ -+H+-----+E+ clht +-H--+ ++ | 1 -----+E+-- ck +-N--+ | | -+H+---- | 100 ++ -----+E+ ++ | +E+-- | | ----+++ | 50 ++ -+E+ ++ | +E+ +++ | | +E+N+-+N+-----+ + + + + + + | 0 ++--E------+------N-------N-------N-------N-------N------N-------N--++ 1 8 16 24 32 40 48 56 64 Number of threads 200K keys, 100 % updates qht +-E--+ clht +-H--+ 160 ++--+------+------+-------+-------+-------+-------+---ck-+-N-----+--++ | + + + + + + + + ----H | 140 ++ +H+-- -+E+ ++ | +++---- ---- | 120 ++ 8 ++------+------++ -+H+ +E+ ++ | 7 ++ +H+---- ++ ---- +++---- | 100 ++ | +E+ | +++ ---+H+ -+E+ ++ | 6 ++ +++ ++ -+H+-- +++---- | 80 ++ 5 ++------N----------+E+-----+E+ ++ | 1 -+H+---- +++ | | -----+E+ | 60 ++ +H+---- +++ ++ | ----+E+ | 40 ++ +H+---- ++ | --+E+ | 20 ++ +E+ ++ | +EE+ + + + + + + + + | 0 ++--+N-N---N------N-------N-------N-------N-------N------N-------N--++ 1 8 16 24 32 40 48 56 64 Number of threads Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <1465412133-3029-13-git-send-email-cota@braap.org> Signed-off-by: Richard Henderson <rth@twiddle.net> |