<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Hello<div><br></div><div>Just wanted to share some results of my analysis.</div><div><br></div><div>I have changed safepoints from reading polling page ( lwu to x0) to writing to polling page ( sw from x0).</div><div><br></div><div>here are results:</div><div><br></div><div><div><font face="PT Mono">polling page  read</font></div><div><font face="PT Mono">Benchmark                                                          Mode  Cnt   Score    Error  Units</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall                            avgt   25  32.192 ?  0.364  ns/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:L1-dcache-load-misses:u    avgt    5   0.001 ?  0.001   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:L1-dcache-loads:u          avgt    5   9.036 ?  0.072   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:L1-dcache-stores:u         avgt    5   0.019 ?  0.025   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:LLC-loads:u                avgt    5   0.005 ?  0.007   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:LLC-stores:u               avgt    5   0.002 ?  0.002   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:branch-misses:u            avgt    5   0.001 ?  0.001   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:branches:u                 avgt    5   4.014 ?  0.029   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:cycles:u                   avgt    5  38.777 ?  2.444   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:instructions:u             avgt    5  15.121 ?  0.200   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:stalled-cycles-frontend:u  avgt    5   0.001 ?  0.002   #/op</font></div></div><div><font face="PT Mono"><br></font></div><div><div><font face="PT Mono">polling page write</font></div><div><font face="PT Mono">Benchmark                                                          Mode  Cnt   Score    Error  Units</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall                            avgt   25  30.326 ?  0.257  ns/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:L1-dcache-load-misses:u    avgt    5   0.001 ?  0.001   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:L1-dcache-loads:u          avgt    5   8.035 ?  0.016   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:L1-dcache-stores:u         avgt    5   1.016 ?  0.012   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:LLC-loads:u                avgt    5   0.004 ?  0.004   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:LLC-stores:u               avgt    5   0.001 ?  0.001   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:branch-misses:u            avgt    5   0.001 ?  0.001   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:branches:u                 avgt    5   4.014 ?  0.007   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:cycles:u                   avgt    5  36.552 ?  1.662   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:instructions:u             avgt    5  15.110 ?  0.062   #/op</font></div><div><font face="PT Mono">InterfaceCalls.testInterfaceCastAndCall:stalled-cycles-frontend:u  avgt    5   0.001 ?  0.001   #/op</font></div><div><br></div><div><br></div><div><br></div><div>Minus one 1 l1 load, Plus one l1 store, it’s obvious. Since stores are cheaper (for cpu core, not for caches), total cycles got reduced.</div></div><div>One another hand, stores storm should generate some traffic from l1d to LLC and then to RAM which may slow down another threads/apps.</div><div><br></div><div>Regards, Vladimir</div></body></html>