From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Keith Packard" Subject: Re: [PATCH] vulkan: Add VK_EXT_calibrated_timestamps extension (radv and anv) [v4] Date: Tue, 16 Oct 2018 15:56:33 -0700 Message-ID: <87r2gp7b6m.fsf@keithp.com> References: <20181015230515.3695-1-keithp@keithp.com> <20181016053150.11453-1-keithp@keithp.com> <87bm7t8z3k.fsf@keithp.com> <8736t58usr.fsf@keithp.com> <87tvll7dha.fsf@keithp.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1149154472==" Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: mesa-dev-bounces@lists.freedesktop.org Sender: "mesa-dev" To: Bas Nieuwenhuizen Cc: mesa-dev , ML dri-devel List-Id: dri-devel@lists.freedesktop.org --===============1149154472== Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Bas Nieuwenhuizen writes: > You can make the monotonic case the same as the raw case if you make > sure to always sample the CPU first by e.g. splitting the loops into > two and doing CPU in the first and GPU in the second. That way you > make the case above impossible. Right, I had thought of that, and it probably solves the problem for us. If more time domains are added, things become 'more complicated' though. > That said "start of the interval of the tick" is kinda arbitrary and > you could pick random other points on that interval, so depending on > what requirements you put on it (i.e. can the chosen position be > different per call, consistent but implicit or explicitly picked which > might be leaked through the interface) the max deviation changes. So > depending on interpretation this thing can be very moot ... It doesn't really matter what phase you use; the timer increments periodically, and what really matters is the time when that happens relative to other clocks changing. =2D-=20 =2Dkeith --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEw4O3eCVWE9/bQJ2R2yIaaQAAABEFAlvGbKEACgkQ2yIaaQAA ABEDcg//ZnFbsYmphPkiuhT2Gb0ZvovLCZ76iSVDrw4nEyr3AfYYf6xPEJs2IZpL wUC2e49suCHCjEWy/IzO9rqcqNGtJ+9jUVFmZey8j8yUeosZ0PqwtQNM96EMinVq mYvyzpcCu6mwP2/dw74/xwzByvm1rtUdcuraQYYVikLjAYch4XmYrKBmrTbvV5uP qCItz5cYDLCuSncV4xSFY4qnYzkFSZN3MTcu96lW1wIpv+47nXrQwNyVb35cqi9M 7BZ5ml6vIq4EuxpuYtMIQD4AUcPLnt3B3S1DIjSaYdZCgz2zS8a/IOBXSq1sxF8y xqUcHg1C8gZDKpigDRnEFxvNw4QR5M67Xu3ocatRkBhVARsmImrXf58+fCN8mQLf 72Q7MaSrvjBCg3x/2nxOiQGlBjAwWDFx4tInmKgV1GVl4RE7oztWFVyahqIH1s0f lozW4TCMt+SB2mchZlvBN689U28j5KxLvs7lHHQvmj5xZn/d66rNV0wQsyIPZMbl gXocpTxns6IDLnclKSTwnabS9gejFw9RC0kpWolKm/jkWCzJl3dmaCbGITA28N2x DQuOOgiMPlEvVu9qY9ROJ9RUI5R58CJWPeNHGc8caSGEg05SN/PKRHdNC1eNyNSB Kj4Puu3+RiE721bEMWllic17cqnhCVSrfo8S85duEBaYh+hNCOw= =aElL -----END PGP SIGNATURE----- --=-=-=-- --===============1149154472== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KbWVzYS1kZXYg bWFpbGluZyBsaXN0Cm1lc2EtZGV2QGxpc3RzLmZyZWVkZXNrdG9wLm9yZwpodHRwczovL2xpc3Rz LmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFuL2xpc3RpbmZvL21lc2EtZGV2Cg== --===============1149154472==--