Re: [Qemu-arm] [PATCH v6 00/73] per-CPU locks

[Richard Henderson]

On 1/29/19 4:46 PM, Emilio G. Cota wrote:
> v5: https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg02979.html
> 
> For context, the goal of this series is to substitute the BQL for the
> per-CPU locks in many places, notably the execution loop in cpus.c.
> This leads to better scalability for MTTCG, since CPUs don't have
> to acquire a contended global lock (the BQL) every time they
> stop executing code.
> 
> See the last commit for some performance numbers.
> 
> After this series, the remaining obstacles to achieving KVM-like
> scalability in MTTCG are: (1) interrupt handling, which
> in some targets requires the BQL, and (2) frequent execution of
> "async safe" work.
> That said, some targets scale great on MTTCG even before this
> series -- for instance, when running a parallel compilation job
> in an x86_64 guest, scalability is comparable to what we get with
> KVM.
> 
> This series is very long. If you only have time to look at a few patches,
> I suggest the following, which do most of the heavy lifting and
> have not yet been reviewed:
> 
> - Patch 7: cpu: make per-CPU locks an alias of the BQL in TCG rr mode
> - Patch 70: cpu: protect CPU state with cpu->lock instead of the BQL
> 
> I've tested all patches with `make check-qtest -j' for all targets.
> The series is checkpatch-clean (just some warnings about __COVERITY__).
> 
> You can fetch the series from:
>   https://github.com/cota/qemu/tree/cpu-lock-v6

Thanks for the patience.  Both Alex and I have now completed review, and I
think this is ready for merge.

There are some patch conflicts with master, so if you can fix those and post a
v7, we'll get it merged right away.


r~