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Re: [Qemu-devel] [RFC PATCH] target-arm/psci.c: wake up sleeping CPUs (M

From: Alexander Spyridakis
Subject: Re: [Qemu-devel] [RFC PATCH] target-arm/psci.c: wake up sleeping CPUs (MTTCG)
Date: Thu, 25 Jun 2015 01:55:27 +0200

On 24 June 2015 at 17:34, Alex Bennée <address@hidden> wrote:
> Testing with Alexander's bare metal syncronisation tests fails in MTTCG
> leaving one CPU spinning forever waiting for the second CPU to wake up.
> We simply need to poke the halt_cond once we have processed the PSCI
> power on call.

Thanks Alex. Works for me, also with qemu_cpu_kick(target_cpu_state)
as Paolo mentioned.

The test seems to stress the current multi-threaded implementation
quite a lot. With 8 CPUs running, the resulting errors are in the
range of 500 per vCPU (10 million iterations).
Performance is another issue as mentioned before, but even more
pronounced with 8 cores. Upstream QEMU needs around 10 seconds to
complete, with multi-threading around 100 seconds for the same test.

Best regards.

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