217742 2020-10-14 17:40:31 -0700 HIDGamepadProvider adds an extra 50ms to all inputs 2021-07-01 13:22:30 -0700 1 1 1 Unclassified WebKit UI Events Safari 14 Mac macOS 10.15 RESOLVED FIXED InRadar P2 Normal --- 1 juberti beidson achristensen beidson webkit-bug-importer oldest_to_newest 1697976 0 juberti 2020-10-14 17:40:31 -0700 When measuring Safari's button-to-photon latency with html5gamepad.com, I noticed that Safari has roughly double the latency of Chrome for wired USB gamepads (108ms vs 56ms). I investigated this a bit and found this code in HIDGamepadProvider which I believe accounts for the difference: https://github.com/WebKit/webkit/blob/950143da027e80924b4bb86defa8a3f21fd3fb1e/Source/WebCore/platform/gamepad/mac/HIDGamepadProvider.cpp#L39 50ms is enormous latency for a gamepad - gaming mice charge a premium in order to deliver ~10ms latency savings. Could this delay be reduced or eliminated? The rationale around this code isn't entirely clear to me: // This isActive check is necessary as we want to delay input notifications from the time of the first input, // and not push the notification out on every subsequent input. if (!m_inputNotificationTimer.isActive()) m_inputNotificationTimer.startOneShot(inputNotificationDelay); 1697982 1 webkit-bug-importer 2020-10-14 17:56:27 -0700 <rdar://problem/70315838> 1698238 2 beidson 2020-10-15 13:03:28 -0700 Definitely room for improvement here. 1701055 3 juberti 2020-10-23 10:26:25 -0700 Note also that GameControllerGamepadProvider also has a 16ms notification delay: https://github.com/WebKit/webkit/blob/950143da027e80924b4bb86defa8a3f21fd3fb1e/Source/WebCore/platform/gamepad/cocoa/GameControllerGamepadProvider.mm#L45 Could anyone comment on the intent behind these delays? 1774152 4 432706 beidson 2021-07-01 10:20:28 -0700 Created attachment 432706 Patch 1774230 5 ews-feeder 2021-07-01 13:22:29 -0700 Committed r279480 (239333@main): <https://commits.webkit.org/239333@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 432706. 432706 2021-07-01 10:20:28 -0700 2021-07-01 13:22:30 -0700 Patch bug-217742-20210701102028.patch text/plain 3109 beidson U3VidmVyc2lvbiBSZXZpc2lvbjogMjc5NDY3CmRpZmYgLS1naXQgYS9Tb3VyY2UvV2ViQ29yZS9D aGFuZ2VMb2cgYi9Tb3VyY2UvV2ViQ29yZS9DaGFuZ2VMb2cKaW5kZXggZjkzODk5OGQ2NDFhMGFi N2VmMmQ5OGY5YjI3ZTg0YWE5OWUzMDQ2ZC4uYzNhNTljODNkYjJkMTJlZjQzM2Q0ODIzNzE4NjQ2 YjdiODk3M2VhNSAxMDA2NDQKLS0tIGEvU291cmNlL1dlYkNvcmUvQ2hhbmdlTG9nCisrKyBiL1Nv dXJjZS9XZWJDb3JlL0NoYW5nZUxvZwpAQCAtMSwzICsxLDMyIEBACisyMDIxLTA3LTAxICBCcmFk eSBFaWRzb24gIDxiZWlkc29uQGFwcGxlLmNvbT4KKworICAgICAgICBISURHYW1lcGFkUHJvdmlk ZXIgYWRkcyBhbiBleHRyYSA1MG1zIHRvIGFsbCBpbnB1dHMKKyAgICAgICAgPHJkYXI6Ly83MDMx NTgzOD4gYW5kIGh0dHBzOi8vYnVncy53ZWJraXQub3JnL3Nob3dfYnVnLmNnaT9pZD0yMTc3NDIK KworICAgICAgICBSZXZpZXdlZCBieSBOT0JPRFkgKE9PUFMhKS4KKworICAgICAgICBObyBuZXcg dGVzdHMuCisgICAgICAgIFRyaWVkIHRvIHdyaXRlIGFuIEFQSSB0ZXN0IHRvIGRyaXZlIGlucHV0 cyBpbiB0aGUgZGVsYXkgcmFuZ2UsIGJ1dCB0aGF0IHdhcyB3YXkgdG9vIGZyYWdpbGUKKyAgICAg ICAgb24gYSBsb2NhbCBkZXZlbG9wZXIgbWFjaGluZSwgbXVjaCBsZXNzIGEgYm90IHRoYXQncyB1 bmRlciBsb2FkLgorCisgICAgICAgIFRoZXNlIGlucHV0IGRlbGF5cyB3ZXJlIGFuIGVhcmx5IGJl c3QtZWZmb3J0IHRvIGdldCBpbnB1dCB0byBsaW5lIHVwIHdpdGggUmFGLCB3aGljaCB0aGUgc3Bl YworICAgICAgICBtZW50aW9ucyBhcyBhIGdvYWwuCisgICAgICAgIAorICAgICAgICBOb3Qgc3Vy ZSBob3cgNTAgc2xpcHBlZCBpbiBmb3IgSElELCB2cyB0aGUgMTYgb24gR0NGLgorICAgICAgICAK KyAgICAgICAgV2hldGhlciBvciBub3QgbGluaW5nIHVwIHBlcmZlY3RseSB3aXRoIFJhRiBpcyBh Y3R1YWxseSBhIHVzZWZ1bCBnb2FsLCBpbiB0aGUgbWVhbnRpbWUgZHJpdmluZworICAgICAgICBp bnB1dCBhcyBxdWlja2x5IGFzIHBvc3NpYmxlIHNlZW1zIG11Y2ggbW9yZSBkZXNpcmFibGUuCisg ICAgICAgIAorICAgICAgICBXZSBzdGlsbCB3YW50IHRvIGNvYWxlc2NlIG11bHRpcGxlIGNsb3Nl IHRvZ2V0aGVyIGlucHV0cyBpbnRvIDEgbG9naWNhbCBldmVudCB0byBzbW9vdGggb3V0IGppdHRl cgorICAgICAgICB3aXRoIGNlcnRhaW4gZGV2aWNlcywgYW5kIHJlZHVjZSBJUEMgYW5kIERPTSBv YmplY3QgY2h1cm4gZHVyaW5nIHJhcGlkIGlucHV0IChvciB3aXRoIGJ1Z2d5IGRldmljZXMpLgor ICAgICAgICAKKyAgICAgICAgSW4gdGVzdGluZyB3aXRoIHdoYXQgSSBoYXZlIG9uIG15IGRlc2ss IHVzaW5nIGEgdHJ1ZSAwLWRlbGF5IHRpbWVyIGZvciB0aGF0IHdhcyBub3QgZGVzaXJhYmxlLgor CisgICAgICAgIEJ1dCAxbXMgc2VlbXMgcGVhY2h5IGtlZW4uCisgICAgICAgIAorICAgICAgICAq IHBsYXRmb3JtL2dhbWVwYWQvY29jb2EvR2FtZUNvbnRyb2xsZXJHYW1lcGFkUHJvdmlkZXIubW06 CisgICAgICAgICogcGxhdGZvcm0vZ2FtZXBhZC9tYWMvSElER2FtZXBhZFByb3ZpZGVyLm1tOgor CiAyMDIxLTA3LTAxICBBbWlyIE1hcmsgSnIgIDxhbWlyX21hcmtAYXBwbGUuY29tPgogCiAgICAg ICAgIFVucmV2aWV3ZWQsIHJldmVydGluZyByMjc5NDUyLgpkaWZmIC0tZ2l0IGEvU291cmNlL1dl YkNvcmUvcGxhdGZvcm0vZ2FtZXBhZC9jb2NvYS9HYW1lQ29udHJvbGxlckdhbWVwYWRQcm92aWRl ci5tbSBiL1NvdXJjZS9XZWJDb3JlL3BsYXRmb3JtL2dhbWVwYWQvY29jb2EvR2FtZUNvbnRyb2xs ZXJHYW1lcGFkUHJvdmlkZXIubW0KaW5kZXggMzg3ZTQzYmM4NjVmMmIyZTA1NGRmNGRhNzkwNDI4 YTIyMzI2OTExNC4uODE3OTRhMmIwYTA2YWViYWJjY2E2MDU3NDMzOWU5MmI0M2IzMzM3MiAxMDA2 NDQKLS0tIGEvU291cmNlL1dlYkNvcmUvcGxhdGZvcm0vZ2FtZXBhZC9jb2NvYS9HYW1lQ29udHJv bGxlckdhbWVwYWRQcm92aWRlci5tbQorKysgYi9Tb3VyY2UvV2ViQ29yZS9wbGF0Zm9ybS9nYW1l cGFkL2NvY29hL0dhbWVDb250cm9sbGVyR2FtZXBhZFByb3ZpZGVyLm1tCkBAIC02OCw3ICs2OCw3 IEBAIGJvb2wgR2FtZUNvbnRyb2xsZXJHYW1lcGFkUHJvdmlkZXI6OndpbGxIYW5kbGVWZW5kb3JB bmRQcm9kdWN0KHVpbnQxNl90IHZlbmRvcklECiAKICNlbmRpZiAvLyAhSEFWRShHQ0NPTlRST0xM RVJfSElEX0RFVklDRV9DSEVDSykKIAotc3RhdGljIGNvbnN0IFNlY29uZHMgaW5wdXROb3RpZmlj YXRpb25EZWxheSB7IDE2X21zIH07CitzdGF0aWMgY29uc3QgU2Vjb25kcyBpbnB1dE5vdGlmaWNh dGlvbkRlbGF5IHsgMV9tcyB9OwogCiBHYW1lQ29udHJvbGxlckdhbWVwYWRQcm92aWRlciYgR2Ft ZUNvbnRyb2xsZXJHYW1lcGFkUHJvdmlkZXI6OnNpbmdsZXRvbigpCiB7CmRpZmYgLS1naXQgYS9T b3VyY2UvV2ViQ29yZS9wbGF0Zm9ybS9nYW1lcGFkL21hYy9ISURHYW1lcGFkUHJvdmlkZXIubW0g Yi9Tb3VyY2UvV2ViQ29yZS9wbGF0Zm9ybS9nYW1lcGFkL21hYy9ISURHYW1lcGFkUHJvdmlkZXIu bW0KaW5kZXggNWRhYTAxYTUyZGQ1MTM3YjJkM2E4MDFjOWU2MmRjNTA4YTdiYzczMy4uZTNkNmZh YzcwNDM2OTZmYzdlZTJhOTIxNWRiMjFhOGY3ZGY4MjVhNSAxMDA2NDQKLS0tIGEvU291cmNlL1dl YkNvcmUvcGxhdGZvcm0vZ2FtZXBhZC9tYWMvSElER2FtZXBhZFByb3ZpZGVyLm1tCisrKyBiL1Nv dXJjZS9XZWJDb3JlL3BsYXRmb3JtL2dhbWVwYWQvbWFjL0hJREdhbWVwYWRQcm92aWRlci5tbQpA QCAtNDMsNyArNDMsNyBAQAogbmFtZXNwYWNlIFdlYkNvcmUgewogCiBzdGF0aWMgY29uc3QgU2Vj b25kcyBjb25uZWN0aW9uRGVsYXlJbnRlcnZhbCB7IDUwMF9tcyB9Owotc3RhdGljIGNvbnN0IFNl Y29uZHMgaGlkSW5wdXROb3RpZmljYXRpb25EZWxheSB7IDUwX21zIH07CitzdGF0aWMgY29uc3Qg U2Vjb25kcyBoaWRJbnB1dE5vdGlmaWNhdGlvbkRlbGF5IHsgMV9tcyB9OwogCiBzdGF0aWMgUmV0 YWluUHRyPENGRGljdGlvbmFyeVJlZj4gZGV2aWNlTWF0Y2hpbmdEaWN0aW9uYXJ5KHVpbnQzMl90 IHVzYWdlUGFnZSwgdWludDMyX3QgdXNhZ2UpCiB7Cg==