Re: [PATCH] bsd-user/main: Allow setting tb-size

[Warner Losh <imp@bsdimp.com>]

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On Thu, Aug 1, 2024 at 2:25 AM Ilya Leoshkevich <iii@linux.ibm.com> wrote:

> On Wed, 2024-07-31 at 15:21 -0600, Warner Losh wrote:
>
> On Wed, Jul 31, 2024 at 8: 45 AM Ilya Leoshkevich <iii@ linux. ibm. com>
> wrote: While qemu-system can set tb-size using -accel tcg,tb-size=n, there
> is no similar knob for qemu-bsd-user. Add one in a way similar to how
> one-insn-per-tb is already
> On Wed, Jul 31, 2024 at 8:45 AM Ilya Leoshkevich <iii@linux.ibm.com>
> wrote:
>
> While qemu-system can set tb-size using -accel tcg,tb-size=n, there
> is no similar knob for qemu-bsd-user. Add one in a way similar to how
> one-insn-per-tb is already handled.
>
>
> Cool! Are you using bsd-user and need this for some reason? Or is this
> purely theoretical? Is there a larger context I can read about somewhere?
>
>
> I needed this on Linux in order to debug an issue where I suspected full
> TB invalidation may be an issue.
> It turned out to be something completely different, but I found it useful:
> setting it to, e.g., 4096 makes full TB invalidation very rare, so if a
> problem is still reproducible, then the root causes is something else.
> Philippe suggested to implement this for BSD as well in order to keep the
> interfaces in sync.
>

Excellent! Thank you for taking the time to do this! And the other bug fix.
Both have been queued to my first post 9.1 pull branch.

Warner

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