On Mon, 26 Nov 2018, Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> wrote: > On Thu, Nov 22, 2018 at 08:54:30AM +0000, Tvrtko Ursulin wrote: >> >> >> On 21/11/2018 22:19, Rodrigo Vivi wrote: >> > On Mon, Nov 19, 2018 at 02:20:55PM -0800, Lucas De Marchi wrote: >> > > On Thu, Nov 08, 2018 at 11:23:46AM +0000, Tvrtko Ursulin wrote: >> > > > >> > > > On 08/11/2018 00:57, Lucas De Marchi wrote: >> > > > > On Wed, Nov 07, 2018 at 10:05:19AM +0000, Tvrtko Ursulin wrote: >> > > > > > >> > > > > > On 06/11/2018 21:51, Lucas De Marchi wrote: >> > > > > > > This is the second version of the series trying to make GEN checks >> > > > > > > more similar. These or roughly the changes from v1: >> > > > > > > >> > > > > > > - We don't have a single macro receiving 2 or 3 parameters. Now there >> > > > > > > is GT_GEN_RANGE(), and GT_GEN(). The firs is the conversion from >> > > > > > > IS_GEN() while the second is the conversion from IS_GEN<N>() >> > > > > > > - Bring GEN_FOREVER back to be used with above macros >> > > > > > > - Patch converting <, <=, ==, >, >= checks using INTEL_GEN() to >> > > > > > > use the macros above was added >> > > > > > > - INTEL_GEN() is removed to avoid it being used when we should prefer >> > > > > > > the new macros >> > > > > > > >> > > > > > > The idea of the names is to pave the way for checks of the display version, >> > > > > > > which would be named DISPLAY_GEN(), DISPLAY_GEN_RANGE(). >> > > > > > > >> > > > > > > In the commit messages we have the scripts to regenerate the patch to make >> > > > > > > it easier to apply after the discussions and also to be able to convert >> > > > > > > inflight patches. >> > > > > > > >> > > > > > > Sorry in advance for the noise this causes in the codebase, but hopefully >> > > > > > > it is for the greater good. >> > > > > > > >> > > > > > > >> > > > > > > Lucas De Marchi (6): >> > > > > > > Revert "drm/i915: Kill GEN_FOREVER" >> > > > > > > drm/i915: replace IS_GEN<N> with GT_GEN(..., N) >> > > > > > > drm/i915: rename IS_GEN9_* to GT_GEN9_* >> > > > > > > drm/i915: replace gen checks using operators by GT_GEN/GT_GEN_RANGE >> > > > > > >> > > > > > I have reservations about this patch, where I think forcing only one flavour >> > > > > > maybe is not the best thing. Because for plain if-ladder cases it feels more >> > > > > > readable to stick with the current scheme of arithmetic comparisons. And it >> > > > > > is more efficient in code as well. >> > > > > > >> > > > > > Range checks are on the other hand useful either when combined in the same >> > > > > > conditional as some other bitmask based test, or when both ends of the >> > > > > > comparison edge are bound. >> > > > > >> > > > > So are you against changing the == to use the macros, changing the >=, >, <, <=, >> > > > > or all of them? >> > > > >> > > > Definitely not all of them. Just plain if ladders I think are definitely >> > > > more readable in source and result in better code in the normal fashion of: >> > > > >> > > > if (gen >= 11) >> > > > else if (gen >= 9) >> > > > else if (gen >= 7) >> > > > ... etc ... >> > > > >> > > > Where I think it makes sense is when either both edges are bound, like: >> > > > >> > > > if (gen < 11 || gen >= 8) >> > > > if (gen >= 10 || gen == 8) >> > > >> > > ok, I will take a look before respinning this. >> > > >> > > > >> > > > But not sure how many of those there are. >> > > > >> > > > What definitely exists in large-ish numbers are: >> > >> > specially on display side... >> > >> > > > >> > > > if (gen >= 11 || IS_PLATFORM) >> > >> > My goal is exactly to organize the gen numbers in a way that >> > we minimize this mix as much as possible. >> > >> > > > >> > > > At some point I had a prototype which puts the gen and platform masks into a >> > > > bag of bits and then, depending on bits locality, this too can be compressed >> > > > to a single bitmask test. However I felt that was going too far, and the >> > > > issue is achieving interesting bits locality for it too work. But I digress. >> > > > >> > > > > Looking at the changes to ==, they seem very reasonable and in a few cases it allowed >> > > > > the next patch to merge them in a GT_GEN_RANGE() -- yes the patch ordering was on >> > > > > purpose to allow that. >> > > > >> > > > Yep those are the good ones. >> > > > >> > > > > The others are indeed debatable. However IMO for the cases it makes sense, >> > > > > there's always the fallback >> > > > > >> > > > > if (dev_priv->info.gen == 10) >> > > > > ... >> > > > > else if (dev_priv->info.gen == 11) >> > > > > ... >> > > > > else if (dev_priv->info.gen < 5) >> > > > > ... >> > > > > >> > > > > We can go on a case by case manner in this patch rather than the mass conversion >> > > > > for these. >> > > > > >> > > > > > >> > > > > > > drm/i915: merge gen checks to use range >> > > > > > > drm/i915: remove INTEL_GEN macro >> > > > > > >> > > > > > I have reservations about this as as well, especially considering the >> > > > > > previous paragraph. But even on it's own I am not sure we want to go back to >> > > > > > more verbose. >> > > > > >> > > > > see above. IMO it's not actually so verbose as one would think. >> > > > > >> > > > > if (INTEL_GEN(dev_priv) == 11) >> > > > > vs >> > > > > if (dev_priv->info.gen == 11) >> > > > >> > > > I think it should be: >> > > > >> > > > if (INTEL_INFO(dev_priv)->gen == 11) >> > > > >> > > > Which is a tiny bit longer.. >> > > >> > > If it's longer, why bother? We could just as well do for the if ladders: >> > > >> > > gen = dev_priv->info.gen; >> > > or >> > > gen = INTEL_INFO(dev_priv)->gen >> > > >> > > In your other series you would be moving gen to a runtime info, so this >> > > would cause the same amount of churn (although I disagree with moving gen to a runtime >> > > info just because of the mock struct). >> > > >> > > >> > > > >> > > > > The "verbose" version is actually one character less and one lookup less >> > > > > to what the macro is doing underneath. Of course that means a lot of churn >> > > > > to the codebase when/if we change where the gen number is located, but that >> > > > > number is at the same place since its introduction in 2010 >> > > > > (commit c96c3a8cb7fadcb33d9a5ebe35fcee8b7d0a7946) >> > > > >> > > > I am pretty sure we went through patches to a) move towards INTEL_INFO and >> > > > b) replace INTEL_INFO(dev_priv)->gen with INTEL_GEN. So I don't see an >> > > > advantage of reverting that, just so that we can lose the IS_ prefix below. >> > > > >> > > > > > Perhaps in the new scheme of things it should be renamed to INTEL_GT_GEN? I >> > > > > > know it doesn't fit nicely with the naming scheme of GT/DISPLAY_GEN.. so >> > > > > > maybe: >> > > > > > >> > > > > > GT_GEN -> IS_GT_GEN >> > > > > > GT_GEN_RANGE -> IS_GT_GEN_RANGE >> > > > > > INTEL_GEN -> GT_GEN (but churn!?) >> > > > > >> > > > > I still think INTEL_GEN() is not bringing much clarity and forcing >> > > > > the other macros to have the IS_ prefix. >> > > > >> > > > Is the IS_ prefix that bad? >> > >> > I personally don't like it... but maybe it is just my bad english?! >> > >> > 1. if gen 9 >> > 2. if is gen 9 >> > 3. if this is a gen 9 platform >> > >> > I like more the option 1... >> > >> > > > >> > > > I agree my idea does not decrease the amount of churn, since it said to >> > > > replace INTEL_GEN with INTEL_GT_GEN. But in the light of the GT/DISPLAY >> > > > split, and if we agree to leave a lot of the arithmetic comparison in >> > > > (dialing down of "drm/i915: replace gen checks using operators by >> > > > GT_GEN/GT_GEN_RANGE"), then it feels going back to INTEL_INFO(dev_priv)->gen >> > > > throughout the code is undoing some work, just so you can remove the >> > > > INTEL_GEN macro instead of renaming it INTEL_GT_GEN. >> > > > >> > > > Don't know, it's my opinion at least and more people are welcome to chime in >> > > > with theirs. >> > > >> > > Any others to chime in on this? Jani, Ville, Rodrigo? >> > >> > I don't like mixed styles much. If we don't kill the macro we will continue >> > having mixed cases. >> > >> > So I'm in favor of the approach of this series here. >> >> Including the removal of INTEL_GEN macro? Or what do you propose for that >> one? Can't be called GT_GEN now since that has been used up... > > Yes, including the removal of INTEL_GEN macro. > > I don't like the mixed styles like using INTEL_GEN(d) > 7 in one place > and INTEL_GEN_RANGE(d, 7, FOREVER) in another place. > > The meaning is the same so we should stick with one of the usages. > > I see that there were many cases where having the info->gen number > directly is useful. But I'd prefer to use that on a direct fashion > rather than keeping this macro. > > Because if we keep the macro developers will eventually end up > adding the mixed style back. > > Using direct info->gen as Lucas already showed has almost same number > of chars than the macro, but requires more attention what is a good > thing. I prefer using INTEL_GEN() because it hides where the gen comes from, and we can change it on a whim. If we keep using dev_priv->info.gen we'll need to change that already when info becomes a pointer, i.e. dev_priv->info->gen. Throughout the codebase. With INTEL_GEN() it's just a couple of places. If mixed use is a problem, then rename gen to __gen. I even sent a patch for it, but didn't get it merged. BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
