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[PATCH bpf V7 1/7] selftests/bpf: xdp_hw_metadata default disable bpf_printk

Jesper Dangaard Brouer posted 7 patches 2 years, 10 months ago
There is a newer version of this series
[PATCH bpf V7 1/7] selftests/bpf: xdp_hw_metadata default disable bpf_printk
Posted by Jesper Dangaard Brouer 2 years, 10 months ago 
The tool xdp_hw_metadata can be used by driver developers
implementing XDP-hints kfuncs.  The tool transfers the
XDP-hints via metadata information to an AF_XDP userspace
process. When everything works the bpf_printk calls are
unncesssary.  Thus, disable bpf_printk by default, but
make it easy to reenable for driver developers to use
when debugging their driver implementation.

This also converts bpf_printk "forwarding UDP:9091 to AF_XDP"
into a code comment.  The bpf_printk's that are important
to the driver developers is when bpf_xdp_adjust_meta fails.
The likely mistake from driver developers is expected to
be that they didn't implement XDP metadata adjust support.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
---
 .../testing/selftests/bpf/progs/xdp_hw_metadata.c  |   16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
index 4c55b4d79d3d..980eb60d8e5b 100644
--- a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
+++ b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
@@ -5,6 +5,19 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_endian.h>
 
+/* Per default below bpf_printk() calls are disabled.  Can be
+ * reenabled manually for convenience by XDP-hints driver developer,
+ * when troublshooting the drivers kfuncs implementation details.
+ *
+ * Remember BPF-prog bpf_printk info output can be access via:
+ *  /sys/kernel/debug/tracing/trace_pipe
+ */
+//#define DEBUG	1
+#ifndef DEBUG
+#undef  bpf_printk
+#define bpf_printk(fmt, ...) ({})
+#endif
+
 struct {
 	__uint(type, BPF_MAP_TYPE_XSKMAP);
 	__uint(max_entries, 256);
@@ -49,11 +62,10 @@ int rx(struct xdp_md *ctx)
 	if (!udp)
 		return XDP_PASS;
 
+	/* Forwarding UDP:9091 to AF_XDP */
 	if (udp->dest != bpf_htons(9091))
 		return XDP_PASS;
 
-	bpf_printk("forwarding UDP:9091 to AF_XDP");
-
 	ret = bpf_xdp_adjust_meta(ctx, -(int)sizeof(struct xdp_meta));
 	if (ret != 0) {
 		bpf_printk("bpf_xdp_adjust_meta returned %d", ret);
Re: [PATCH bpf V7 1/7] selftests/bpf: xdp_hw_metadata default disable bpf_printk
Posted by Stanislav Fomichev 2 years, 10 months ago 
On Sat, Apr 8, 2023 at 12:24 PM Jesper Dangaard Brouer
<brouer@redhat.com> wrote:
>
> The tool xdp_hw_metadata can be used by driver developers
> implementing XDP-hints kfuncs.  The tool transfers the
> XDP-hints via metadata information to an AF_XDP userspace
> process. When everything works the bpf_printk calls are
> unncesssary.  Thus, disable bpf_printk by default, but
> make it easy to reenable for driver developers to use
> when debugging their driver implementation.
>
> This also converts bpf_printk "forwarding UDP:9091 to AF_XDP"
> into a code comment.  The bpf_printk's that are important
> to the driver developers is when bpf_xdp_adjust_meta fails.
> The likely mistake from driver developers is expected to
> be that they didn't implement XDP metadata adjust support.
>
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> ---
>  .../testing/selftests/bpf/progs/xdp_hw_metadata.c  |   16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> index 4c55b4d79d3d..980eb60d8e5b 100644
> --- a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> +++ b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> @@ -5,6 +5,19 @@
>  #include <bpf/bpf_helpers.h>
>  #include <bpf/bpf_endian.h>
>
> +/* Per default below bpf_printk() calls are disabled.  Can be
> + * reenabled manually for convenience by XDP-hints driver developer,
> + * when troublshooting the drivers kfuncs implementation details.
> + *
> + * Remember BPF-prog bpf_printk info output can be access via:
> + *  /sys/kernel/debug/tracing/trace_pipe
> + */
> +//#define DEBUG        1
> +#ifndef DEBUG
> +#undef  bpf_printk
> +#define bpf_printk(fmt, ...) ({})
> +#endif

Are you planning to eventually do somethike similar to what I've
mentioned in [0]? If not, should I try to send a patch?

0: https://lore.kernel.org/netdev/CAKH8qBupRYEg+SPMTMb4h532GESG7P1QdaFJ-+zrbARVN9xrdA@mail.gmail.com/

> +
>  struct {
>         __uint(type, BPF_MAP_TYPE_XSKMAP);
>         __uint(max_entries, 256);
> @@ -49,11 +62,10 @@ int rx(struct xdp_md *ctx)
>         if (!udp)
>                 return XDP_PASS;
>
> +       /* Forwarding UDP:9091 to AF_XDP */
>         if (udp->dest != bpf_htons(9091))
>                 return XDP_PASS;
>
> -       bpf_printk("forwarding UDP:9091 to AF_XDP");
> -
>         ret = bpf_xdp_adjust_meta(ctx, -(int)sizeof(struct xdp_meta));
>         if (ret != 0) {
>                 bpf_printk("bpf_xdp_adjust_meta returned %d", ret);
>
>
Re: [PATCH bpf V7 1/7] selftests/bpf: xdp_hw_metadata default disable bpf_printk
Posted by Jesper Dangaard Brouer 2 years, 10 months ago 
On 12/04/2023 00.42, Stanislav Fomichev wrote:
> On Sat, Apr 8, 2023 at 12:24 PM Jesper Dangaard Brouer
> <brouer@redhat.com> wrote:
>>
>> The tool xdp_hw_metadata can be used by driver developers
>> implementing XDP-hints kfuncs.  The tool transfers the
>> XDP-hints via metadata information to an AF_XDP userspace
>> process. When everything works the bpf_printk calls are
>> unncesssary.  Thus, disable bpf_printk by default, but
>> make it easy to reenable for driver developers to use
>> when debugging their driver implementation.
>>
>> This also converts bpf_printk "forwarding UDP:9091 to AF_XDP"
>> into a code comment.  The bpf_printk's that are important
>> to the driver developers is when bpf_xdp_adjust_meta fails.
>> The likely mistake from driver developers is expected to
>> be that they didn't implement XDP metadata adjust support.
>>
>> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
>> ---
>>   .../testing/selftests/bpf/progs/xdp_hw_metadata.c  |   16 ++++++++++++++--
>>   1 file changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
>> index 4c55b4d79d3d..980eb60d8e5b 100644
>> --- a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
>> +++ b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
>> @@ -5,6 +5,19 @@
>>   #include <bpf/bpf_helpers.h>
>>   #include <bpf/bpf_endian.h>
>>
>> +/* Per default below bpf_printk() calls are disabled.  Can be
>> + * reenabled manually for convenience by XDP-hints driver developer,
>> + * when troublshooting the drivers kfuncs implementation details.
>> + *
>> + * Remember BPF-prog bpf_printk info output can be access via:
>> + *  /sys/kernel/debug/tracing/trace_pipe
>> + */
>> +//#define DEBUG        1
>> +#ifndef DEBUG
>> +#undef  bpf_printk
>> +#define bpf_printk(fmt, ...) ({})
>> +#endif
> 
> Are you planning to eventually do somethike similar to what I've
> mentioned in [0]? If not, should I try to send a patch?

See next patch:
  - [PATCH bpf V7 2/7] selftests/bpf: Add counters to xdp_hw_metadata

where I add these counters :-)

> 
> 0: https://lore.kernel.org/netdev/CAKH8qBupRYEg+SPMTMb4h532GESG7P1QdaFJ-+zrbARVN9xrdA@mail.gmail.com/
>
Re: [PATCH bpf V7 1/7] selftests/bpf: xdp_hw_metadata default disable bpf_printk
Posted by Stanislav Fomichev 2 years, 10 months ago 
On 04/12, Jesper Dangaard Brouer wrote:
> 
> On 12/04/2023 00.42, Stanislav Fomichev wrote:
> > On Sat, Apr 8, 2023 at 12:24 PM Jesper Dangaard Brouer
> > <brouer@redhat.com> wrote:
> > > 
> > > The tool xdp_hw_metadata can be used by driver developers
> > > implementing XDP-hints kfuncs.  The tool transfers the
> > > XDP-hints via metadata information to an AF_XDP userspace
> > > process. When everything works the bpf_printk calls are
> > > unncesssary.  Thus, disable bpf_printk by default, but
> > > make it easy to reenable for driver developers to use
> > > when debugging their driver implementation.
> > > 
> > > This also converts bpf_printk "forwarding UDP:9091 to AF_XDP"
> > > into a code comment.  The bpf_printk's that are important
> > > to the driver developers is when bpf_xdp_adjust_meta fails.
> > > The likely mistake from driver developers is expected to
> > > be that they didn't implement XDP metadata adjust support.
> > > 
> > > Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> > > ---
> > >   .../testing/selftests/bpf/progs/xdp_hw_metadata.c  |   16 ++++++++++++++--
> > >   1 file changed, 14 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> > > index 4c55b4d79d3d..980eb60d8e5b 100644
> > > --- a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> > > +++ b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> > > @@ -5,6 +5,19 @@
> > >   #include <bpf/bpf_helpers.h>
> > >   #include <bpf/bpf_endian.h>
> > > 
> > > +/* Per default below bpf_printk() calls are disabled.  Can be
> > > + * reenabled manually for convenience by XDP-hints driver developer,
> > > + * when troublshooting the drivers kfuncs implementation details.
> > > + *
> > > + * Remember BPF-prog bpf_printk info output can be access via:
> > > + *  /sys/kernel/debug/tracing/trace_pipe
> > > + */
> > > +//#define DEBUG        1
> > > +#ifndef DEBUG
> > > +#undef  bpf_printk
> > > +#define bpf_printk(fmt, ...) ({})
> > > +#endif
> > 
> > Are you planning to eventually do somethike similar to what I've
> > mentioned in [0]? If not, should I try to send a patch?
> 
> See next patch:
>  - [PATCH bpf V7 2/7] selftests/bpf: Add counters to xdp_hw_metadata
> 
> where I add these counters :-)

Oh, nice, let me take a look. I was assuming v7 is mostly the same as
v6..
 
> > 
> > 0: https://lore.kernel.org/netdev/CAKH8qBupRYEg+SPMTMb4h532GESG7P1QdaFJ-+zrbARVN9xrdA@mail.gmail.com/
> > 
>
Re: [PATCH bpf V7 1/7] selftests/bpf: xdp_hw_metadata default disable bpf_printk
Posted by Jesper Dangaard Brouer 2 years, 10 months ago 
On 12/04/2023 18.06, Stanislav Fomichev wrote:
> On 04/12, Jesper Dangaard Brouer wrote:
>> On 12/04/2023 00.42, Stanislav Fomichev wrote:
>>> On Sat, Apr 8, 2023 at 12:24 PM Jesper Dangaard Brouer
>>>>
[...]
>>>
>>> Are you planning to eventually do somethike similar to what I've
>>> mentioned in [0]? If not, should I try to send a patch?
>>
>> See next patch:
>>   - [PATCH bpf V7 2/7] selftests/bpf: Add counters to xdp_hw_metadata
>>
>> where I add these counters :-)
> 
> Oh, nice, let me take a look. I was assuming v7 is mostly the same as
> v6..
>   

Alexei explicitly asked for these changes to be included in V7.
Notice, I've already send out a [V8] (addressing Simon's notes).
Please take a look at V8 instead of V7.
We are at RC6 and I hope we soon have something we can agree on.


[V8] 
https://lore.kernel.org/all/168130333143.150247.11159481574477358816.stgit@firesoul/

[patchwork] 
https://patchwork.kernel.org/project/netdevbpf/list/?series=739144&state=%2A&archive=both


--Jesper
Re: [PATCH bpf V7 1/7] selftests/bpf: xdp_hw_metadata default disable bpf_printk
Posted by Simon Horman 2 years, 10 months ago 
On Sat, Apr 08, 2023 at 09:24:41PM +0200, Jesper Dangaard Brouer wrote:
> The tool xdp_hw_metadata can be used by driver developers
> implementing XDP-hints kfuncs.  The tool transfers the
> XDP-hints via metadata information to an AF_XDP userspace
> process. When everything works the bpf_printk calls are
> unncesssary.  Thus, disable bpf_printk by default, but
> make it easy to reenable for driver developers to use
> when debugging their driver implementation.
> 
> This also converts bpf_printk "forwarding UDP:9091 to AF_XDP"
> into a code comment.  The bpf_printk's that are important
> to the driver developers is when bpf_xdp_adjust_meta fails.
> The likely mistake from driver developers is expected to
> be that they didn't implement XDP metadata adjust support.
> 
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> ---
>  .../testing/selftests/bpf/progs/xdp_hw_metadata.c  |   16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> index 4c55b4d79d3d..980eb60d8e5b 100644
> --- a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> +++ b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> @@ -5,6 +5,19 @@
>  #include <bpf/bpf_helpers.h>
>  #include <bpf/bpf_endian.h>
>  
> +/* Per default below bpf_printk() calls are disabled.  Can be
> + * reenabled manually for convenience by XDP-hints driver developer,
> + * when troublshooting the drivers kfuncs implementation details.

Hi Jesper,

a minor nit from my side:

nit: s/troublshooting/troubleshooting/

...

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