On Fri, Dec 15, 2023 at 02:36:21AM +0000, Dmitry Safonov wrote:
Sample output:
1..36 # 1106[lib/setup.c:207] rand seed 1660754406 TAP version 13 ok 1 Worst case connect 512 keys: min=0ms max=1ms mean=0.583329ms stddev=0.076376 ok 2 Connect random-search 512 keys: min=0ms max=1ms mean=0.53412ms stddev=0.0516779 ok 3 Worst case delete 512 keys: min=2ms max=11ms mean=6.04139ms stddev=0.245792 ok 4 Add a new key 512 keys: min=0ms max=13ms mean=0.673415ms stddev=0.0820618 ok 5 Remove random-search 512 keys: min=5ms max=9ms mean=6.65969ms stddev=0.258064 ok 6 Remove async 512 keys: min=0ms max=0ms mean=0.041825ms stddev=0.0204512 ok 7 Worst case connect 1024 keys: min=0ms max=2ms mean=0.520357ms stddev=0.0721358 ok 8 Connect random-search 1024 keys: min=0ms max=2ms mean=0.535312ms stddev=0.0517355 ok 9 Worst case delete 1024 keys: min=5ms max=9ms mean=8.27219ms stddev=0.287614 ok 10 Add a new key 1024 keys: min=0ms max=1ms mean=0.688121ms stddev=0.0829531 ok 11 Remove random-search 1024 keys: min=5ms max=9ms mean=8.37649ms stddev=0.289422 ok 12 Remove async 1024 keys: min=0ms max=0ms mean=0.0457096ms stddev=0.0213798 ok 13 Worst case connect 2048 keys: min=0ms max=2ms mean=0.748804ms stddev=0.0865335 ok 14 Connect random-search 2048 keys: min=0ms max=2ms mean=0.782993ms stddev=0.0625697 ok 15 Worst case delete 2048 keys: min=5ms max=10ms mean=8.23106ms stddev=0.286898 ok 16 Add a new key 2048 keys: min=0ms max=1ms mean=0.812988ms stddev=0.0901658 ok 17 Remove random-search 2048 keys: min=8ms max=9ms mean=8.84949ms stddev=0.297481 ok 18 Remove async 2048 keys: min=0ms max=0ms mean=0.0297223ms stddev=0.0172402 ok 19 Worst case connect 4096 keys: min=1ms max=5ms mean=1.53352ms stddev=0.123836 ok 20 Connect random-search 4096 keys: min=1ms max=5ms mean=1.52226ms stddev=0.0872429 ok 21 Worst case delete 4096 keys: min=5ms max=9ms mean=8.25874ms stddev=0.28738 ok 22 Add a new key 4096 keys: min=0ms max=3ms mean=1.67382ms stddev=0.129376 ok 23 Remove random-search 4096 keys: min=5ms max=10ms mean=8.26178ms stddev=0.287433 ok 24 Remove async 4096 keys: min=0ms max=0ms mean=0.0340009ms stddev=0.0184393 ok 25 Worst case connect 8192 keys: min=2ms max=4ms mean=2.86208ms stddev=0.169177 ok 26 Connect random-search 8192 keys: min=2ms max=4ms mean=2.87592ms stddev=0.119915 ok 27 Worst case delete 8192 keys: min=6ms max=11ms mean=7.55291ms stddev=0.274826 ok 28 Add a new key 8192 keys: min=1ms max=5ms mean=2.56797ms stddev=0.160249 ok 29 Remove random-search 8192 keys: min=5ms max=10ms mean=7.14002ms stddev=0.267208 ok 30 Remove async 8192 keys: min=0ms max=0ms mean=0.0320066ms stddev=0.0178904 ok 31 Worst case connect 16384 keys: min=5ms max=6ms mean=5.55334ms stddev=0.235655 ok 32 Connect random-search 16384 keys: min=5ms max=6ms mean=5.52614ms stddev=0.166225 ok 33 Worst case delete 16384 keys: min=5ms max=11ms mean=7.39109ms stddev=0.271866 ok 34 Add a new key 16384 keys: min=2ms max=4ms mean=3.35799ms stddev=0.183248 ok 35 Remove random-search 16384 keys: min=5ms max=8ms mean=6.86078ms stddev=0.261931 ok 36 Remove async 16384 keys: min=0ms max=0ms mean=0.0302384ms stddev=0.0173892 # Totals: pass:36 fail:0 xfail:0 xpass:0 skip:0 error:0
From the output it's visible that the current simplified approach with linked-list of MKTs scales quite fine even for thousands of keys. And that also means that the majority of the time for delete is eaten by synchronize_rcu() [which I can confirm separately by tracing].
Signed-off-by: Dmitry Safonov dima@arista.com
Tested-by: Hangbin Liu liuhangbin@gmail.com