On Tue, Aug 25, 2026 at 5:50 PM Richard Henderson <[email protected]> wrote: > > On 8/22/26 12:08, Matt Turner wrote: > > The cost is memory: the cache grows from 64 KiB to 1 MiB per vCPU. That > > is easy to justify for a single-vCPU linux-user process and less obvious > > for system emulation with many vCPUs, so this may want to be sized by > > target or made tunable rather than raised unconditionally. > > Why do you believe linux-user processes are single-threaded? I suppose > when emulating /bin a fair few of them are, but...
I don't -- I'd conflated "one process" with "one CPUState". linux-user creates a CPUState per guest thread, so a threaded guest pays the megabyte per thread, just as system emulation pays it per vCPU. Commit message fixed. The sizing question stays open, which is why the patch says so. I don't have a threaded workload where 64 KiB is the better trade and would welcome one.
