Re: [PATCH] LoongArch: Set 4 * (issue rate) as the default for -falign-functions and -falign-loops

[Lulu Cheng <chenglulu@loongson.cn>]

在 2023/6/12 下午5:19, Xi Ruoyao 写道:
> On Tue, 2023-05-30 at 09:30 +0800, Lulu Cheng wrote:
>> 在 2023/5/29 下午2:09, Xi Ruoyao 写道:
>>> On Tue, 2023-04-18 at 21:06 +0800, Lulu Cheng wrote:
>>>> Hi, ruoyao:
>>>>
>>>> Thank you so much for making this submission. But we are testing
>>>> the
>>>> impact of these two alignment parameters
>>>>
>>>> (also including -falign-jumps and -falign-lables ) on performance.
>>>> So
>>>> before the result comes out, this patch will
>>>>
>>>> not be merged into the main branch for the time being.
>>> Hi!
>>>
>>> Is there an estimate when the benchmark will be done?  If it will be
>>> done soon I'll wait for the result before performing a full system
>>> rebuild, otherwise I'll use my gut feeling to specify a -falign-
>>> functions= value for the build :).
>>>
>> Sorry for taking so long to reply to the email. From our current test
>> results,
>>
>> the performance of the SPEC is best when combined with -falign-
>> loops=16,
>>
>> -falign-jumps=16, -falign-functions=32 and -falign-lables=16.
> I've completed a system rebuild with -falign-
> {jumps,functions,labels}=16.  I've missed -falign-loops=16 but the doc
> says -falign-labels=16 implies -falign-jumps=16 and -falign-loops=16 (if
> -falign-jumps or -falign-loops are not set explicitly with a larger
> value).
>
> I'll make a patch to set -falign-functions=32 and -falign-labels=16 with
> -mtune={la464,loongarch64} after setting a basic develop environment on
> the new system...  And I'm wondering if things will change with LA664
> :).
>
>
We haven't tested it on LA664 yet, so it's not clear whether this is 
consistent with LA464.

This test will not be done on LA664 anytime soon. But once I've done the 
test, I'll let you know by email.