Profile: https://share.firefox.dev/424Ybas On some of our Windows perf machines in CI we can see that Windows Defender is using CPU in the background during an sp3 run, to scan files such as this one: `\Device\HarddiskVolume3\Users\task_177576942453562\AppData\Local\Temp\rust_mozprofileGC97Ut\cache2\entries\C29AB3AE0D6130114272543B8C6D086E005A5235` This profile was recorded with xperf and converted with samply. The Defender markers (`StreamScanRequestTask/win`) are from the `Microsoft-Antimalware-Engine` provider. `` xperf -start "NT Kernel Logger" -on PROC_THREAD+LOADER+PROFILE+CSWITCH -stackwalk PROFILE+CSWITCH -BufferSize 1024 -start usersession -on Microsoft-Windows-Kernel-Power+Microsoft-Windows-Kernel-Processor-Power+Microsoft-Antimalware-Engine -BufferSize 1024 xperf -stop "NT Kernel Logger" -stop usersession -d xperf-speedometer3.etl samply import --unknown-event-markers xperf-speedometer3.etl ``` --- One could argue that we should change the settings on our performance testing machines so that Windows Defender doesn't use CPU. But on the other hand, it's not an unrealistic testing environment - many of our users will have Defender enabled. I have not checked how Defender's CPU usage compares when running sp3 in other browsers.
Bug 2031458 Comment 0 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
Profile: https://share.firefox.dev/424Ybas On some of our Windows perf machines in CI we can see that Windows Defender is using CPU in the background during an sp3 run, to scan files such as this one: `\Device\HarddiskVolume3\Users\task_177576942453562\AppData\Local\Temp\rust_mozprofileGC97Ut\cache2\entries\C29AB3AE0D6130114272543B8C6D086E005A5235` This profile was recorded with xperf and converted with samply. The Defender markers (`StreamScanRequestTask/win`) are from the `Microsoft-Antimalware-Engine` provider. ``` xperf -start "NT Kernel Logger" -on PROC_THREAD+LOADER+PROFILE+CSWITCH -stackwalk PROFILE+CSWITCH -BufferSize 1024 -start usersession -on Microsoft-Windows-Kernel-Power+Microsoft-Windows-Kernel-Processor-Power+Microsoft-Antimalware-Engine -BufferSize 1024 xperf -stop "NT Kernel Logger" -stop usersession -d xperf-speedometer3.etl samply import --unknown-event-markers xperf-speedometer3.etl ``` --- One could argue that we should change the settings on our performance testing machines so that Windows Defender doesn't use CPU. But on the other hand, it's not an unrealistic testing environment - many of our users will have Defender enabled. I have not checked how Defender's CPU usage compares when running sp3 in other browsers.