Re: [Qemu-devel] [PATCH 4/4] target/s390x: Re-implement a few EXECUTE target insns directly

From: Aurelien Jarno <aurelien@aurel32.net>
To: Richard Henderson <rth@twiddle.net>
Cc: qemu-devel@nongnu.org, thuth@redhat.com
Subject: Re: [Qemu-devel] [PATCH 4/4] target/s390x: Re-implement a few EXECUTE target insns directly
Date: Fri, 26 May 2017 01:12:59 +0200	[thread overview]
Message-ID: <20170525231259.nkzs2rdmscufnezw@aurel32.net> (raw)
In-Reply-To: <20170524220827.21154-5-rth@twiddle.net>

On 2017-05-24 15:08, Richard Henderson wrote:
> While the previous patch is required for proper conformance,
> the vast majority of target insns are MVC and XC for implementing
> memmove and memset respectively.  The next most common are CLC,
> TR, and SVC.
> 
> Implementing these (and a few others for which we already have
> an implementation) directly is faster than going through full
> translation to a TB.
> 
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  target/s390x/mem_helper.c | 66 ++++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 51 insertions(+), 15 deletions(-)

I have mixed feelings about this patch. On one side it is correct. On
the other side, I don't know if it really worth it. With the goto_ptr
optimization, it can be executed quite fast once it has been translated
once.

So in short, I leave you decide:

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net