On Wed, Mar 31, 2021 at 08:39:57AM +0000, Juraj Linkeš wrote: > > > > -----Original Message----- > > From: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com> > > Sent: Tuesday, March 30, 2021 2:39 AM > > To: Jerin Jacob <jerinjac...@gmail.com>; Juraj Linkeš > > <juraj.lin...@pantheon.tech> > > Cc: Bruce Richardson <bruce.richard...@intel.com>; Ruifeng Wang > > <ruifeng.w...@arm.com>; vcchu...@amazon.com; Dharmik Thakkar > > <dharmik.thak...@arm.com>; hemant.agra...@nxp.com; Ajit Khaparde > > (ajit.khapa...@broadcom.com) <ajit.khapa...@broadcom.com>; > > ferruh.yi...@intel.com; abo...@pensando.io; lir...@marvell.com; > > dev@dpdk.org; nd <n...@arm.com>; Honnappa Nagarahalli > > <honnappa.nagaraha...@arm.com>; nd <n...@arm.com> > > Subject: RE: [PATCH v16 1/3] build: disable/enable drivers in Arm builds > > > > <snip> > > > > > > <removed parts which I think are not that relevant> > > > > > > > > > > > > > > > > The blocklist is, I think, agreed upon by everyone. > > > > > > > > > > > > The question is whether we want to support the > > > > > > > > > > > > allowlist alongside it and there seem to be enough > > > > > > > > > > > > reasons to do > > > that. > > > > > > > > > > > Sorry, may be this is answered already, but, what > > > > > > > > > > > additional benefit does allowlist provide over the > > > > > > > > > > > blocklist? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > VPP could use it: > > > > > > > > > > https://gerrit.fd.io/r/gitweb?p=vpp.git;a=blob;f=build/e > > > > > > > > > > xt > > > > > > > > > > erna > > > > > > > > > > l/pa > > > > > > > > > > ckag es/dpdk > > > > > > > > > > .mk;h=c35ac84c27b19411a0cfdf9a3524fdf36024762c;hb=HEAD > > > > > > > > > > > > > > > > > > > > They're disabling almost everything so an allowlist would > > > > > > > > > > fit there. > > > > > > > > > > And they won't need to update the list when a new driver > > > > > > > > > > is added (which they won't need). > > > > > > > > > This is different from how we started this discussion. The > > > > > > > > > current discussion was for DPDK internal use. But the one > > > > > > > > > you are referencing above is for users of DPDK. I am fine > > > > > > > > > for providing the allow list for the users of DPDK. But > > > > > > > > > for DPDK internal, I think block list is > > > > > > > enough. > > > > > > > > > > > > > > > > > > > > > > > > > That's an interesting suggestion. Jerin, what do you think? > > > > > > > > Why did you > > > > > > > want to have an allowlist? Would this work? > > > > > > > > > > > > > > # The very reason why VPP chooses to have allow list so that > > > > > > > they can control what needs to include. > > > > > > > # Another use case is like, in SoCs have fixed internal > > > > > > > devices, we can have optimized build for that can have only > > > > > > > allow list of the drivers that care about # For server market, > > > > > > > block list makes sense # For embedded SoC, allow list makes sense. > > > > > > For the embedded SoC, IMO, the upstream project could allow the > > > > > > compilation > > > > > for wider set of PMDs/libs. May be the end customer can use the > > > > > allow list to compile/use what is required? > > > > > > > > > > Just to understand, how end customer can enable allow list, if > > > > > DPDK build system does not support it? > > > > > Also to understand, If we are supporting blocklist, why not have > > > > > allowlist (I mean, both of them) as both are required as it caters > > > > > different use case as mention above. We can not emulate allowlist > > > > > with blocklist as each version of DPDK will have new libraries and > > > > > PMD's > > > which end user has no clue. Right? > > > > > > > > > I think, that is the reason why VPP is doing the allow list. > > > > > > > > I'm not sure what you mean by this, but to clarify, VPP likely would > > > > be using > > > the allowlist in this fashion, but that is not an arm specific > > > usecase. I think what Honnappa wanted to see was how the allowlist > > > could be used in an arm usecase (such as using it in an SoC > > > configuration). > > > > > > There is nothing arm-specific here. Right? allowlist will be common > > > and will be used by all architecture. Right? > > Nothing Arm specific. I think for generic Arm servers platforms we can make > > sure that we allow for compilation of all the DPDK code. We can go ahead > > with > > implementing the allow list. > > > > I tried to actually use an allowlist and there are some problems with > building apps and tests. When I tried to enable a random driver, such as > common/sfc_efx, I've ran into dependency issues with apps: > app/meson.build:53:3: ERROR: Tried to get unknown variable > "static_rte_bus_vdev". > > This is because bus/vdev is not enabled (the allowlist only enabled > net/sfc_efx). When I implemented dependency discovery in apps similar to > which exists for drivers/libs, I was then unable to build tests (which is a > special case app): > app/test/meson.build:427:1: ERROR: Tried to get unknown variable > "static_rte_bus_pci". > > This is becasue bus/pci is not enabled. If I understand the code correctly, > the test dependencies are not matched to each test, meaning we can't disable > the tests for which we don't have dependencies - we can only disable all > tests. > > In general, this problem also affects the blocklist, i.e. meson build > -Ddisable_drivers=bus/pci produces > drivers/net/hinic/base/meson.build:34:0: ERROR: Unknown variable > "static_rte_bus_pci". > For blocklists, this is seldom going to be a problem, since most users won't > disable "core" drivers. > > I'm not sure what is the best course of action. We can implement the > allowlist and then we'll leave it up to implementers to implement allowlists > that produce a working build. We could then optionally address the dependency > issues brought by disabled drivers in a separate patch. > > Maybe we can just have a list of "core" drivers that can never be disabled > (either using blocklists or allowlists)? > > Bruce, what do you think? > Hi,
from my experience this mainly seems to affect the bus drivers, specifically pci and vdev buses, which seem to be assumed to be always enabled. I agree it's probably not a real problem right now, though it would be nice for some testing purposes to have a build possible with "disable_drivers=*/*". For a solution I am happy for us to have whichever is easiest to implement - either refusing disabling of bus/pci and bus/vdev, or fixing the tests and apps to allow them to be built with reduced functionality. Apart from those two drivers, I would hope that disabling everything else works. If not, we should definitely fix it. /Bruce
