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charset=us-ascii Content-Disposition: inline In-Reply-To: <20240510-okay-trade-8826cb134979@spud> On Fri, May 10, 2024 at 09:25:37AM +0100, Conor Dooley wrote: > On Thu, May 09, 2024 at 03:55:12PM -0700, Charlie Jenkins wrote: > > On Thu, May 09, 2024 at 11:08:34PM +0100, Conor Dooley wrote: > > > > Maybe if you read what I wrote you'd see what I was getting at, or maybe > > > not as I might not have been sufficiently clear. I'm not saying that this > > > particular optimisation is not worth having, but rather than I wanted to > > > > I seem to frequently give you the impression that I don't read what you > > say before responding. > > Does it happen frequently? I don't really recall it annoying me before. > > > What we each view as "important" in the kernel is > > different so we come from different places when approaching a problem. I > > respond in the way that I do not because I am not listening to you, but > > simply because I have a different opinion and I am not explaining that > > properly. > > If you're trying to describe a different opinion, responding to the bit > I was talking about, as you do below in your latest response is ideal. > Responding inline but not actually addressing the points I was making > did make me think you were [un]intentionally ignoring what I was trying > to say. > > > > see why this particular optimisation was worth maintaining 3 code paths > > > > I interpreted the "3 code paths" as with Zbb + 64 bit, with Zbb + 32 > > bit, and without Zbb. I directly responded to that by saying that we > > could eliminate all of the code paths that are not Zbb + 64 bit could be > > eliminated. I should have given performance numbers for these alternate > > cases too, and somebody should have asked. I agree that performance > > needs justification, and I understand that I did not provide ample > > justification in this patch. All other architectures optimized these > > code paths so I figured that was sufficient justification for riscv to > > do the same, but I understand that it is not. > > And hey, if you look at the commit in question, who acked it? I'm just > saying that I think we should have a higher standard going forwards. > > > > for but the commit message does not detail any of the benefits, and > > > looking at the cover I discovered that it was not tested in hardware nor > > > seemingly with a real test case. > > > > It's hard when riscv currently is very focused on microcontrollers. > > Zbb is actually implemented in hardware, so testing it in the real world > is not a barrier. Palmer probably has a JH7110 board that someone gave > to him is not using... > > > These changes are in order to help future hardware that is more focused > > about performance. > > I'm not replying to most of your response rn, got other stuff to do, but > what I was trying to say is that I think the point at which optimisations > for future hardware/extensions should be merged is the point at which > those extensions are no longer future. > > > That's why I contribute this upstream with the hope > > that other people, like me, care about performance. > > Heh, that could be read to mean that I do not care about performance, > which wouldn't be true. > > Cheers, > Conor. This is all a good perspective for me to keep in mind when I look into performance improvements. I will try to get my hands on some hardware that I can use to test so I can have some real numbers! - Charlie