lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <CANr-f5zzQ6_UsOdLZK7b-k5Jy4qhdGJ4_D2irK-S0FzhE5u3rQ@mail.gmail.com> Date: Sat, 16 Apr 2022 00:04:20 +0200 From: Gerhard Engleder <gerhard@...leder-embedded.com> To: Richard Cochran <richardcochran@...il.com> Cc: Vinicius Costa Gomes <vinicius.gomes@...el.com>, yangbo.lu@....com, David Miller <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, mlichvar@...hat.com, netdev <netdev@...r.kernel.org> Subject: Re: [PATCH net-next v2 4/5] ptp: Support late timestamp determination > > For igc and tsnep the 16 bytes in front of the RX frame exist anyway. > > So this would be a minimal solution with best performance as a first > > step. A lookup for netdev/phc can be added in the future if there is > > a driver, which needs that. > > It is a design mistake to base new kernel interfaces on hardware > quirks. > > > Is it worth posting an implementation in that direction? > > Sure, but please make thoughts about how this would work for the > non-igc world. > > IIRC one of the nxp switches also has such counters? You can start > with that. I did some measurements (A53, 1.2GHz): netdev lookup and call to my driver takes ~400ns. ptp_convert_timestamp() takes ~6000ns, I assume because of class_find_device_by_name() call. So eliminating the netdev lookup is the wrong optimisation target. I will try to do it like that: - normal, driver without cycles support: use hwtstamps->hwtstamp directly (not changed) - driver with cycles support: netdev lookup for address/cookie conversion to hwtstamp (newly implemented) - vclock: slow path with phc lookup (not changed) Gerhard
Powered by blists - more mailing lists