[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v3 00/22] re-factor softfloat and add fp16 funct
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH v3 00/22] re-factor softfloat and add fp16 functions |
Date: |
Mon, 29 Jan 2018 11:14:19 -0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 |
On 01/28/2018 12:41 PM, Emilio G. Cota wrote:
> On Thu, Jan 25, 2018 at 12:59:56 +0000, Alex Bennée wrote:
>> Howard Spoelstra <address@hidden> writes:
> (snip)
>>> Recent tcg optimisations had improved processor and floating point
>>> performance considerably, but that gain seems to be more than lost for
>>> the floating point performance.
>>>
>>> Any idea what is causing this?
>>
>> Well we expected a little degradation but it's a bit more than I
>> expected.
>
> It's pretty bad (almost a 2X mean slowdown) for the three FP workloads
> in dbt-bench:
I have not yet tried dbt-bench, but on another test case I was able to recover
all of the performance by marking all of the helpers inline. I'm somewhat
disappointed by the compiler here.
r~
- Re: [Qemu-devel] [PATCH v3 22/22] fpu/softfloat: re-factor sqrt, (continued)