1 Commits

Author	SHA1	Message	Date
Emilio G. Cota	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>	2016-06-11 17:11:16 -07:00