From mboxrd@z Thu Jan 1 00:00:00 1970 From: zhoucm1 Subject: Re: Support for amdgpu VM update via CPU on large-bar systems Date: Fri, 12 May 2017 16:25:30 +0800 Message-ID: <5915717A.3000209@amd.com> References: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============2008339003==" Return-path: In-Reply-To: List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: amd-gfx-bounces-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org Sender: "amd-gfx" To: "Kasiviswanathan, Harish" , "amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org" --===============2008339003== Content-Type: multipart/alternative; boundary="------------090904000302060209080403" --------------090904000302060209080403 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit On 2017年05月10日 05:47, Kasiviswanathan, Harish wrote: > Hi, > > Please review the patch set that supports amdgpu VM update via CPU. This feature provides improved performance for compute (HSA) where mapping / unmapping is carried out (by Kernel) independent of command submissions (done directly by user space). This version doesn't support shadow copy of VM page tables for CPU based update. I think your improved performance is from less waiting for cs, generally, SDMA engine updating page table is faster than CPU, otherwise we don't need sdma for updating PT. So whether your this improvement proves we have some redundant sync when mapping / unmapping, if yes, we should fix that, then not sure if CPU method is need or not. Regards, David Zhou > > Best Regards, > Harish > > > > _______________________________________________ > amd-gfx mailing list > amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org > https://lists.freedesktop.org/mailman/listinfo/amd-gfx --------------090904000302060209080403 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: 8bit
On 2017年05月10日 05:47, Kasiviswanathan, Harish wrote:
Hi,

Please review the patch set that supports amdgpu VM update via CPU. This feature provides improved performance for compute (HSA) where mapping / unmapping is carried out (by Kernel) independent of command submissions (done directly by user space). This version doesn't support shadow copy of VM page tables for CPU based update.
I think your improved performance is from less waiting for cs, generally, SDMA engine updating page table is faster than CPU, otherwise we don't need sdma for updating PT.
So whether your this improvement proves we have some redundant sync when mapping / unmapping, if yes, we should fix that, then not sure if CPU method is need or not.

Regards,
David Zhou

Best Regards,
Harish




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