On 04.01.2018 19:51, Jan Kokemüller wrote: > It is possible to emulate a high resolution counter with a thread that > continuously increments a variable [1]. This is the reason why browser > vendors are currently disabling the SharedArrayBuffer feature [2]. > > [1]: > https://gist.github.com/ErikAugust/724d4a969fb2c6ae1bbd7b2a9e3d4bb6#gistcomment-2311156 > [2]: > https://blog.mozilla.org/security/2018/01/03/mitigations-landing-new-class-timing-attack/
I tried the phtread example from [1] but even with some tweaking is does not work at all. This is a multiprocessor system, with moderate load. As far as I understand the matter, it can only work if both threads share the same cpu cache, otherwise the counter variable is either never up-to-date, or has to be fetched and stored from/to memory, which is way too slow for this purpose. Any suggestions ? --- CPU: Intel(R) Xeon(R) CPU E5420 @ 2.50GHz (2500.14-MHz K8-class CPU) FreeBSD/SMP: Multiprocessor System Detected: 8 CPUs FreeBSD/SMP: 2 package(s) x 4 core(s) _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
