The BPF selftests have build time dependencies on cutting edge versions of tools in the BPF ecosystem including LLVM which are more involved to satisfy than more typical requirements like installing a package from your distribution. This causes issues for users looking at kselftest in as a whole who find that a default build of kselftest fails and that resolving this is time consuming and adds administrative overhead. The fast pace of BPF development and the need for a full BPF stack to do substantial development or validation work on the code mean that people working directly on it don't see a reasonable way to keep supporting older environments without causing problems with the usability of the BPF tests in BPF development so these requirements are unlikely to be relaxed in the immediate future.
There is already support for skipping targets so in order to reduce the barrier to entry for people interested in kselftest as a whole let's use that to skip the BPF tests by default when people work with the top level kselftest build system. Users can still build the BPF selftests as part of the wider kselftest build by specifying SKIP_TARGETS, including setting an empty SKIP_TARGETS to build everything. They can also continue to build the BPF selftests individually in cases where they are specifically focused on BPF.
This isn't ideal since it means people will need to take special steps to build the BPF tests but the dependencies mean that realistically this is already the case to some extent and it makes it easier for people to pick up and work with the other selftests which is hopefully a net win.
Signed-off-by: Mark Brown broonie@kernel.org --- tools/testing/selftests/Makefile | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index afbab4aeef3c..8a917cb4426a 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -77,8 +77,10 @@ TARGETS += zram TARGETS_HOTPLUG = cpu-hotplug TARGETS_HOTPLUG += memory-hotplug
-# User can optionally provide a TARGETS skiplist. -SKIP_TARGETS ?= +# User can optionally provide a TARGETS skiplist. By default we skip +# BPF since it has cutting edge build time dependencies which require +# more effort to install. +SKIP_TARGETS ?= bpf ifneq ($(SKIP_TARGETS),) TMP := $(filter-out $(SKIP_TARGETS), $(TARGETS)) override TARGETS := $(TMP)
On Thu, Dec 10, 2020 at 06:52:33PM +0000, Mark Brown wrote:
The BPF selftests have build time dependencies on cutting edge versions of tools in the BPF ecosystem including LLVM which are more involved to satisfy than more typical requirements like installing a package from your distribution. This causes issues for users looking at kselftest in as a whole who find that a default build of kselftest fails and that resolving this is time consuming and adds administrative overhead. The fast pace of BPF development and the need for a full BPF stack to do substantial development or validation work on the code mean that people working directly on it don't see a reasonable way to keep supporting older environments without causing problems with the usability of the BPF tests in BPF development so these requirements are unlikely to be relaxed in the immediate future.
There is already support for skipping targets so in order to reduce the barrier to entry for people interested in kselftest as a whole let's use that to skip the BPF tests by default when people work with the top level kselftest build system. Users can still build the BPF selftests as part of the wider kselftest build by specifying SKIP_TARGETS, including setting an empty SKIP_TARGETS to build everything. They can also continue to build the BPF selftests individually in cases where they are specifically focused on BPF.
This isn't ideal since it means people will need to take special steps to build the BPF tests but the dependencies mean that realistically this is already the case to some extent and it makes it easier for people to pick up and work with the other selftests which is hopefully a net win.
Signed-off-by: Mark Brown broonie@kernel.org
tools/testing/selftests/Makefile | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index afbab4aeef3c..8a917cb4426a 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -77,8 +77,10 @@ TARGETS += zram TARGETS_HOTPLUG = cpu-hotplug TARGETS_HOTPLUG += memory-hotplug -# User can optionally provide a TARGETS skiplist. -SKIP_TARGETS ?= +# User can optionally provide a TARGETS skiplist. By default we skip +# BPF since it has cutting edge build time dependencies which require +# more effort to install. +SKIP_TARGETS ?= bpf
I'm fine with this, but I'd rather make an obvious second step right away and move selftests/bpf into a different directory.
On 12/10/20 12:11 PM, Alexei Starovoitov wrote:
On Thu, Dec 10, 2020 at 06:52:33PM +0000, Mark Brown wrote:
The BPF selftests have build time dependencies on cutting edge versions of tools in the BPF ecosystem including LLVM which are more involved to satisfy than more typical requirements like installing a package from your distribution. This causes issues for users looking at kselftest in as a whole who find that a default build of kselftest fails and that resolving this is time consuming and adds administrative overhead. The fast pace of BPF development and the need for a full BPF stack to do substantial development or validation work on the code mean that people working directly on it don't see a reasonable way to keep supporting older environments without causing problems with the usability of the BPF tests in BPF development so these requirements are unlikely to be relaxed in the immediate future.
There is already support for skipping targets so in order to reduce the barrier to entry for people interested in kselftest as a whole let's use that to skip the BPF tests by default when people work with the top level kselftest build system. Users can still build the BPF selftests as part of the wider kselftest build by specifying SKIP_TARGETS, including setting an empty SKIP_TARGETS to build everything. They can also continue to build the BPF selftests individually in cases where they are specifically focused on BPF.
This isn't ideal since it means people will need to take special steps to build the BPF tests but the dependencies mean that realistically this is already the case to some extent and it makes it easier for people to pick up and work with the other selftests which is hopefully a net win.
Signed-off-by: Mark Brown broonie@kernel.org
tools/testing/selftests/Makefile | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index afbab4aeef3c..8a917cb4426a 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -77,8 +77,10 @@ TARGETS += zram TARGETS_HOTPLUG = cpu-hotplug TARGETS_HOTPLUG += memory-hotplug -# User can optionally provide a TARGETS skiplist. -SKIP_TARGETS ?= +# User can optionally provide a TARGETS skiplist. By default we skip +# BPF since it has cutting edge build time dependencies which require +# more effort to install. +SKIP_TARGETS ?= bpf
I'm fine with this, but I'd rather make an obvious second step right away and move selftests/bpf into a different directory.
Why is this an obvious second step? If people want to run bpf, they can build and run. How does moving it out of selftests directory help? It would become harder on users that want to run the test.
I don't support moving bpf out of selftests directory in the interest of Linux kernel quality and validation.
Let's think big picture and kernel community as a whole.
thanks, -- Shuah
On Thu, Dec 10, 2020 at 04:41:33PM -0700, Shuah Khan wrote:
On 12/10/20 12:11 PM, Alexei Starovoitov wrote:
I'm fine with this, but I'd rather make an obvious second step right away and move selftests/bpf into a different directory.
Why is this an obvious second step? If people want to run bpf, they can build and run. How does moving it out of selftests directory help? It would become harder on users that want to run the test.
I don't support moving bpf out of selftests directory in the interest of Linux kernel quality and validation.
Let's think big picture and kernel community as a whole.
Yeah, I don't see an obvious motivation for doing that either - what problem does it solve? For people running suites it's helpful to have fewer testsuites and test infrastructures to integrate with. The work needed for the dependencies is going to be the same no matter where we put the tests and moving out of the shared infrastructure creates some additional work.
On Thu, Dec 10, 2020 at 06:52:33PM +0000, Mark Brown wrote:
The BPF selftests have build time dependencies on cutting edge versions of tools in the BPF ecosystem including LLVM which are more involved to satisfy than more typical requirements like installing a package from your distribution. This causes issues for users looking at kselftest in as a whole who find that a default build of kselftest fails and that resolving this is time consuming and adds administrative overhead. The fast pace of BPF development and the need for a full BPF stack to do substantial development or validation work on the code mean that people working directly on it don't see a reasonable way to keep supporting older environments without causing problems with the usability of the BPF tests in BPF development so these requirements are unlikely to be relaxed in the immediate future.
There is already support for skipping targets so in order to reduce the barrier to entry for people interested in kselftest as a whole let's use that to skip the BPF tests by default when people work with the top level kselftest build system. Users can still build the BPF selftests as part of the wider kselftest build by specifying SKIP_TARGETS, including setting an empty SKIP_TARGETS to build everything. They can also continue to build the BPF selftests individually in cases where they are specifically focused on BPF.
This isn't ideal since it means people will need to take special steps to build the BPF tests but the dependencies mean that realistically this is already the case to some extent and it makes it easier for people to pick up and work with the other selftests which is hopefully a net win.
Signed-off-by: Mark Brown broonie@kernel.org
Why not just remove the line which adds bpf to TARGETS? This has the same effect, but doesn't require an emtpy SKIP_TARGETS to run them. We have testing scripts which use 'make TARGETS=bpf ...' which will have to be updated, and I doubt we are the only ones.
I also feel like this creates confusing semantics around SKIP_TARGETS. If I don't supply a value then I don't get the bpf selftests, but then if I try to use SKIP_TARGETS to skip some other test suddenly I do get them. That's counterintuitive.
I also wanted to point out that the net/test_bpf.sh selftest requires having the test_bpf module from the bpf selftest build. So when the bpf selftests aren't built this test is guaranteed to fail. Though it would be nice if the net selftests didn't require building the bpf self tests in order to pass.
Thanks, Seth
tools/testing/selftests/Makefile | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index afbab4aeef3c..8a917cb4426a 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -77,8 +77,10 @@ TARGETS += zram TARGETS_HOTPLUG = cpu-hotplug TARGETS_HOTPLUG += memory-hotplug -# User can optionally provide a TARGETS skiplist. -SKIP_TARGETS ?= +# User can optionally provide a TARGETS skiplist. By default we skip +# BPF since it has cutting edge build time dependencies which require +# more effort to install. +SKIP_TARGETS ?= bpf ifneq ($(SKIP_TARGETS),) TMP := $(filter-out $(SKIP_TARGETS), $(TARGETS)) override TARGETS := $(TMP) -- 2.20.1
On Wed, Dec 16, 2020 at 04:05:58PM -0600, Seth Forshee wrote:
On Thu, Dec 10, 2020 at 06:52:33PM +0000, Mark Brown wrote:
as part of the wider kselftest build by specifying SKIP_TARGETS, including setting an empty SKIP_TARGETS to build everything. They can also continue to build the BPF selftests individually in cases where they are specifically focused on BPF.
Why not just remove the line which adds bpf to TARGETS? This has the same effect, but doesn't require an emtpy SKIP_TARGETS to run them. We have testing scripts which use 'make TARGETS=bpf ...' which will have to be updated, and I doubt we are the only ones.
I also feel like this creates confusing semantics around SKIP_TARGETS. If I don't supply a value then I don't get the bpf selftests, but then if I try to use SKIP_TARGETS to skip some other test suddenly I do get them. That's counterintuitive.
That's what I did first, it's also messy just differently. If you don't add bpf to TARGETS then if you do what's needed to get it building it becomes inconvenient to run it as part of running everything else at the top level since you need to enumerate all the targets. It felt like skipping is what we're actually doing here and it seems like those actively working with BPF will be used to having to update things in their environment. People who start using SKIP_TARGETS are *probably* going to find out about it from the Makefile anyway so will see the default that's there.
Fundamentally having such demanding build dependencies is always going to result in some kind of mess, it's just where we push it.
I also wanted to point out that the net/test_bpf.sh selftest requires having the test_bpf module from the bpf selftest build. So when the bpf selftests aren't built this test is guaranteed to fail. Though it would be nice if the net selftests didn't require building the bpf self tests in order to pass.
Right, that's a separate issue - the net tests should really skip that if they don't have BPF, as we do for other runtime detectable dependencies. It's nowhere near as severe as failing to build though.
On 12/17/20 6:07 AM, Mark Brown wrote:
On Wed, Dec 16, 2020 at 04:05:58PM -0600, Seth Forshee wrote:
On Thu, Dec 10, 2020 at 06:52:33PM +0000, Mark Brown wrote:
as part of the wider kselftest build by specifying SKIP_TARGETS, including setting an empty SKIP_TARGETS to build everything. They can also continue to build the BPF selftests individually in cases where they are specifically focused on BPF.
Why not just remove the line which adds bpf to TARGETS? This has the same effect, but doesn't require an emtpy SKIP_TARGETS to run them. We have testing scripts which use 'make TARGETS=bpf ...' which will have to be updated, and I doubt we are the only ones.
I would prefer leaving bpf in the main Makefile TARGETS. This will be useful to users that have their systems setup for bpf builds.
I also feel like this creates confusing semantics around SKIP_TARGETS. If I don't supply a value then I don't get the bpf selftests, but then if I try to use SKIP_TARGETS to skip some other test suddenly I do get them. That's counterintuitive.
That's what I did first, it's also messy just differently. If you don't add bpf to TARGETS then if you do what's needed to get it building it becomes inconvenient to run it as part of running everything else at the top level since you need to enumerate all the targets. It felt like skipping is what we're actually doing here and it seems like those actively working with BPF will be used to having to update things in their environment. People who start using SKIP_TARGETS are *probably* going to find out about it from the Makefile anyway so will see the default that's there.
Fundamentally having such demanding build dependencies is always going to result in some kind of mess, it's just where we push it.
I also wanted to point out that the net/test_bpf.sh selftest requires having the test_bpf module from the bpf selftest build. So when the bpf selftests aren't built this test is guaranteed to fail. Though it would be nice if the net selftests didn't require building the bpf self tests in order to pass.
Right, that's a separate issue - the net tests should really skip that if they don't have BPF, as we do for other runtime detectable dependencies. It's nowhere near as severe as failing to build though.
Correct. This has to be handled as a run-time dependency check and skip instead of fail.
thanks, -- Shuah
On 12/17/20 8:53 AM, Shuah Khan wrote:
On 12/17/20 6:07 AM, Mark Brown wrote:
On Wed, Dec 16, 2020 at 04:05:58PM -0600, Seth Forshee wrote:
On Thu, Dec 10, 2020 at 06:52:33PM +0000, Mark Brown wrote:
as part of the wider kselftest build by specifying SKIP_TARGETS, including setting an empty SKIP_TARGETS to build everything. They can also continue to build the BPF selftests individually in cases where they are specifically focused on BPF.
Applied to linuxkselftest fixes for rc2
thanks, -- Shuah
linux-kselftest-mirror@lists.linaro.org
-
Alexei Starovoitov -
Mark Brown -
Seth Forshee -
Shuah Khan