Re: [Qemu-discuss] SMP support in the user-mode

[Peter Maydell]

On 24 August 2016 at 07:10, Soramichi AKIYAMA <address@hidden> wrote:
> I am currently using the user-mode (not system-mode) of QEMU
> for performance analysis of multi-threaded programs.
>
> Although there are several discussions about SMP for the system-mode,
> I cannot find a thorough documentation about SMP for the user-mode.
> (I only found this: 
> http://qemu.weilnetz.de/qemu-tech.html#clone_0028_0029-system-call-and-threads)
> Is it correctly supported, or in work-in-progress, or in any other state?

So for a long time supporting multi-threaded guests in QEMU
usermode wasn't supported at all -- it failed very frequently with
various crashes. We've fixed some of the most common
crashes, and so starting from 2.7 it is "supported but buggy".
That means that mostly it'll work but you will probably find
bugs, and if you do then we're interested in looking at them
and trying to fix them.

thanks
-- PMM