Re: [PATCH RFC 10/11] um: Delay timer_read only in possible busy loops in TT-mode

2023-11-10 Thread Johannes Berg
On Fri, 2023-11-10 at 16:54 +0100, Benjamin Beichler wrote: > Am 06.11.2023 um 21:51 schrieb Johannes Berg: > > On Fri, 2023-11-03 at 16:41 +, Benjamin Beichler wrote: > > > This slows down external TT-mode as more simulation roundtrips are > > > required, and it unnecessarily affects the deter

Re: [PATCH RFC 10/11] um: Delay timer_read only in possible busy loops in TT-mode

2023-11-10 Thread Benjamin Berg
On Fri, 2023-11-10 at 16:54 +0100, Benjamin Beichler wrote: > At the moment, we haven't patched the random device that fetches random > bytes from the host (do you already have a patch for this?), > so complete repeatability isn't guaranteed at the moment. However, that > could be a logical next

Re: [PATCH RFC 10/11] um: Delay timer_read only in possible busy loops in TT-mode

2023-11-10 Thread Benjamin Beichler
Am 06.11.2023 um 21:51 schrieb Johannes Berg: On Fri, 2023-11-03 at 16:41 +, Benjamin Beichler wrote: This slows down external TT-mode as more simulation roundtrips are required, and it unnecessarily affects the determinism and accuracy of the simulation. I still don't think this is really

Re: [PATCH RFC 10/11] um: Delay timer_read only in possible busy loops in TT-mode

2023-11-06 Thread Johannes Berg
On Fri, 2023-11-03 at 16:41 +, Benjamin Beichler wrote: > This slows down external TT-mode as more simulation roundtrips are > required, and it unnecessarily affects the determinism and accuracy of > the simulation. I still don't think this is really true, it doesn't really affect determinism?

[PATCH RFC 10/11] um: Delay timer_read only in possible busy loops in TT-mode

2023-11-03 Thread Benjamin Beichler
Some userspace programs use the current timestamp as a looping condition (directly or indirectly), which can lead to infinite loops in TT-mode since the timestamp doesn't change until the next time step. Commit 065038706f77 ("um: Support time travel mode") introduced a workaround by always inserti