Re: ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

On Fri, Aug 23, 2019 at 2:15 AM Maxim Kuvyrkov wrote: > > ... > The other 1/3 will require much more work -- neon intrinsics needs to be > converted from inline asms to GCC builtins, so that we can attach scheduler > descriptions to them. Please do. I know of at least two libraries that

Re: ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

Hi Maxim, Thank you very much for investigating on this matter. Yupeng Chang Aug 31 2019 On Fri, Aug 30, 2019 at 2:36 PM Maxim Kuvyrkov wrote: > Hi Yupeng, > > I've filed https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91598 . All > future discussions will be in that bug entry. > > Regards, > >

Re: ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

Hi Yupeng, I've filed https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91598 . All future discussions will be in that bug entry. Regards, -- Maxim Kuvyrkov www.linaro.org > On Aug 30, 2019, at 8:53 AM, Yupeng Chang wrote: > > Hi Maxim, > This patch does fix part of the regression. > I don't

Re: ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

Hi Maxim, This patch does fix part of the regression. I don't see other regression on other software with this patch. I'm waiting for more updates / fixes from you. And thank you very much for your work! Yupeng Chang Aug 30 2019 On Thu, Aug 29, 2019 at 10:51 PM Maxim Kuvyrkov wrote: > Hi

Re: ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

Hi Yupeng, Any update? -- Maxim Kuvyrkov www.linaro.org > On Aug 23, 2019, at 12:09 PM, Yupeng Chang wrote: > > Hi Maxim, > I applied this patch to ARM GCC 8.3 2019.03, and it works! > GCC 8.3 with this patch can generate code much faster than the GCC 8.3 > without this patch. > > But the

Re: ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

Hi Maxim, I applied this patch to ARM GCC 8.3 2019.03, and it works! GCC 8.3 with this patch can generate code much faster than the GCC 8.3 without this patch. But the code is still slightly slower than it generated by GCC 7.x I'll do more test to see if there are other regressions. Yupeng

Re: ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

Hi Yupeng, Thanks for the offer. Attached is a patch against trunk, and it fixes about 2/3 of the regression. You should be able to apply it to arm-8-branch or gcc-8-branch as well (the only important part are changes to autopref_rank_for_schedule). The other 1/3 will require much more work

Re: ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

Hi Maxim, If you have any patches that need to be tested, you can send them to me. I can help you test this. Yupeng Chang Aug 23 2019 On Wed, Aug 21, 2019 at 10:21 PM Maxim Kuvyrkov wrote: > Hi Yupeng, > > Great testcase, thanks! > > I've investigated this, and there are two separate changes

Re: ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

Hi Maxim, Thank you very much for looking into this ! Hope you can fix this regression and bring performance back to GCC! :D Yupeng Chang Aug 22 2019 On Wed, Aug 21, 2019 at 10:21 PM Maxim Kuvyrkov wrote: > Hi Yupeng, > > Great testcase, thanks! > > I've investigated this, and there are two

Re: ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

Hi Yupeng, Great testcase, thanks! I've investigated this, and there are two separate changes between GCC 7 and GCC 8 each causing half of the regression. The first regression is due compiler making unlucky decisions. Before the regression compiler just got lucky, and I'll look into bringing

Re: ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

Hi Maxim, Attached is the testcase. Please follow these steps to test: 1. download GCC 8.3 from: https://developer.arm.com/-/media/Files/downloads/gnu-a/8.3-2019.03/binrel/gcc-arm-8.3-2019.03-x86_64-aarch64-linux-gnu.tar.xz?revision=2e88a73f-d233-4f96-b1f4-d8b36e9bb0b9=en 2. download GCC 7.4

Re: ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

Hi Maxim, Thank you for your reply! I'll summarize a testcase for you! Yupeng Chang Aug 21 2019 On Tue, Aug 20, 2019 at 9:15 PM Maxim Kuvyrkov wrote: > Hi Yupeng, > > There are many changes from Linaro GCC 7.x to ARM GCC 8.x, so it is > difficult to guess what may be going wrong. > > Do you

Re: ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

Hi Yupeng, There are many changes from Linaro GCC 7.x to ARM GCC 8.x, so it is difficult to guess what may be going wrong. Do you have a testcase that you can share? With a testcase we can investigate the problem and, possibly, fix it. Regards, -- Maxim Kuvyrkov www.linaro.org > On Aug

ARM GCC 8.x Performance Dropping Compared to Linaro GCC 7.x

Hi Dear Linaro Team, I recently found a very strange issue regarding the code performance. I have a loop written in GCC NEON. The binary of this coded generated by Linaro GCC 7.x is much faster than it generated by ARM GCC 8.x My CPU is ARM Cortex-A53 AARCH64. The compile option is: -Wall -O3