Hi Luiz,
ma, 2025-03-31 kello 11:59 -0400, Luiz Augusto von Dentz kirjoitti:
> Hi Pauli,
>
> On Sun, Mar 30, 2025 at 8:16 AM Pauli Virtanen <pav@xxxxxx> wrote:
> >
> > Add some tests for BPF timestamping on Bluetooth sockets.
> >
> > These require additional tester kernel config, and at build time
> > the vmlinux image.
> >
> > Add cgroup mount to test-runner.
> >
> > Add documentation to tester config for this.
> >
> > Add tests:
> >
> > ISO Send - TX BPF Timestamping
> > ---
> >
> > Notes:
> > This probably needs to wait for the corresponding kernel patch series to
> > settle down.
> >
> > Makefile.tools | 29 ++++++
> > configure.ac | 36 ++++++-
> > doc/test-runner.rst | 26 ++++-
> > doc/tester.config | 5 +
> > tools/iso-tester.c | 71 ++++++++++++-
> > tools/test-runner.c | 1 +
> > tools/tester.bpf.c | 92 +++++++++++++++++
> > tools/tester.bpf.h | 7 ++
>
> Usually we only do one . for source files, so names shall probably be
> tester-bpf.{c,h}.
Ok. The .bpf.c convention was used used in some places.
> > tools/tester.h | 244 ++++++++++++++++++++++++++++++++++++--------
> > 9 files changed, 463 insertions(+), 48 deletions(-)
> > create mode 100644 tools/tester.bpf.c
> > create mode 100644 tools/tester.bpf.h
> >
> > diff --git a/Makefile.tools b/Makefile.tools
> > index e60c31b1d..a35af54fc 100644
> > --- a/Makefile.tools
> > +++ b/Makefile.tools
> > @@ -144,6 +144,7 @@ tools_l2cap_tester_SOURCES = tools/l2cap-tester.c tools/tester.h monitor/bt.h \
> > emulator/smp.c
> > tools_l2cap_tester_LDADD = lib/libbluetooth-internal.la \
> > src/libshared-glib.la $(GLIB_LIBS)
> > +tools_l2cap_tester_CPPFLAGS = $(AM_CPPFLAGS) $(GLIB_CFLAGS)
> >
> > tools_rfcomm_tester_SOURCES = tools/rfcomm-tester.c monitor/bt.h \
> > emulator/hciemu.h emulator/hciemu.c \
> > @@ -191,6 +192,7 @@ tools_sco_tester_SOURCES = tools/sco-tester.c tools/tester.h monitor/bt.h \
> > emulator/smp.c
> > tools_sco_tester_LDADD = lib/libbluetooth-internal.la \
> > src/libshared-glib.la $(GLIB_LIBS)
> > +tools_sco_tester_CPPFLAGS = $(AM_CPPFLAGS) $(GLIB_CFLAGS)
> >
> > tools_hci_tester_SOURCES = tools/hci-tester.c monitor/bt.h
> > tools_hci_tester_LDADD = src/libshared-glib.la $(GLIB_LIBS)
> > @@ -212,6 +214,7 @@ tools_iso_tester_SOURCES = tools/iso-tester.c tools/tester.h monitor/bt.h \
> > emulator/smp.c
> > tools_iso_tester_LDADD = lib/libbluetooth-internal.la \
> > src/libshared-glib.la $(GLIB_LIBS)
> > +tools_iso_tester_CPPFLAGS = $(AM_CPPFLAGS) $(GLIB_CFLAGS)
> >
> > tools_ioctl_tester_SOURCES = tools/ioctl-tester.c monitor/bt.h \
> > emulator/hciemu.h emulator/hciemu.c \
> > @@ -221,6 +224,32 @@ tools_ioctl_tester_SOURCES = tools/ioctl-tester.c monitor/bt.h \
> > emulator/smp.c
> > tools_ioctl_tester_LDADD = lib/libbluetooth-internal.la \
> > src/libshared-glib.la $(GLIB_LIBS)
> > +
> > +if TESTING_BPF
> > +tools/vmlinux.h: $(BPF_VMLINUX)
> > + bpftool btf dump file $(BPF_VMLINUX) format c > $@.new
> > + mv -f $@.new $@
> > +
> > +tools/tester.bpf.o: $(srcdir)/tools/tester.bpf.c tools/vmlinux.h
> > + $(CLANG_BPF) -Wall -Werror -Os -g --target=bpf -Itools -c -o $@ $<
> > +
> > +tools/tester.skel.h: tools/tester.bpf.o
> > + bpftool gen skeleton $< > $@.new
> > + mv -f $@.new $@
> > +
> > +tools_sco_tester_SOURCES += $(builddir)/tools/tester.skel.h
> > +tools_iso_tester_SOURCES += $(builddir)/tools/tester.skel.h
> > +tools_l2cap_tester_SOURCES += $(builddir)/tools/tester.skel.h
> > +
> > +tools_sco_tester_CPPFLAGS += -I$(builddir)/tools $(LIBBPF_CFLAGS)
> > +tools_iso_tester_CPPFLAGS += -I$(builddir)/tools $(LIBBPF_CFLAGS)
> > +tools_l2cap_tester_CPPFLAGS += -I$(builddir)/tools $(LIBBPF_CFLAGS)
> > +
> > +tools_sco_tester_LDADD += $(LIBBPF_LIBS)
> > +tools_iso_tester_LDADD += $(LIBBPF_LIBS)
> > +tools_l2cap_tester_LDADD += $(LIBBPF_LIBS)
> > +endif
> > +
> > endif
> >
> > if TOOLS
> > diff --git a/configure.ac b/configure.ac
> > index 0fa49f686..627b91e77 100644
> > --- a/configure.ac
> > +++ b/configure.ac
> > @@ -390,10 +390,38 @@ AC_ARG_ENABLE(testing, AS_HELP_STRING([--enable-testing],
> > AM_CONDITIONAL(TESTING, test "${enable_testing}" = "yes")
> >
> > if (test "${enable_testing}" = "yes"); then
> > - AC_CHECK_DECLS([SOF_TIMESTAMPING_TX_COMPLETION, SCM_TSTAMP_COMPLETION],
> > - [], [], [[#include <time.h>
> > - #include <linux/errqueue.h>
> > - #include <linux/net_tstamp.h>]])
> > + AC_CHECK_DECLS([SOF_TIMESTAMPING_TX_COMPLETION, SCM_TSTAMP_COMPLETION],
> > + [], [], [[#include <time.h>
> > + #include <linux/errqueue.h>
> > + #include <linux/net_tstamp.h>]])
> > +fi
> > +
> > +AC_ARG_ENABLE(testing-bpf, AS_HELP_STRING([--enable-testing-bpf[=PATH/TO/VMLINUX]],
> > + [enable BPF testing tools]),
> > + [enable_testing_bpf=yes; enable_testing_bpf_arg=${enableval}],
> > + [enable_bpf=no])
> > +AM_CONDITIONAL(TESTING_BPF, test "${enable_testing_bpf}" = "yes")
> > +
> > +if (test "${enable_testing_bpf}" = "yes"); then
> > + AC_ARG_VAR(CLANG_BPF, [CLANG compiler (for BPF)])
> > + AC_ARG_VAR(BPFTOOL, [bpftool])
> > + AC_ARG_VAR(BPF_VMLINUX, [vmlinux image to use for BPF testing])
> > + AC_PATH_PROG([CLANG_BPF], [clang], "no")
> > + if (test "${CLANG_BPF}" == "no"); then
> > + AC_MSG_ERROR([clang for BPF missing])
> > + fi
> > + AC_PATH_PROG([BPFTOOL], [bpftool], "no")
> > + if (test "${BPFTOOL}" == "no"); then
> > + AC_MSG_ERROR([bpftool missing])
> > + fi
> > + PKG_CHECK_MODULES(LIBBPF, libbpf >= 1.4, [], [AC_MSG_ERROR([libbpf missing])])
> > + if (test "${enable_testing_bpf_arg}" != "yes"); then
> > + BPF_VMLINUX=${enable_testing_bpf_arg}
> > + elif (test "${BPF_VMLINUX}" = ""); then
> > + BPF_VMLINUX=/sys/kernel/btf/vmlinux
> > + fi
> > + AC_MSG_NOTICE([using BPF_VMLINUX=${BPF_VMLINUX} for BPF testing])
> > + AC_DEFINE(HAVE_BPF, 1, [Define to 1 if bpf testing is required])
> > fi
> >
> > AC_ARG_ENABLE(experimental, AS_HELP_STRING([--enable-experimental],
> > diff --git a/doc/test-runner.rst b/doc/test-runner.rst
> > index 423a9379c..549b2bcba 100644
> > --- a/doc/test-runner.rst
> > +++ b/doc/test-runner.rst
> > @@ -91,8 +91,8 @@ Bluetooth
> >
> > CONFIG_UHID=y
> >
> > -Lock debuging
> > --------------
> > +Lock debugging
> > +--------------
> >
> > To catch locking related issues the following set of kernel config
> > options may be useful:
> > @@ -110,6 +110,19 @@ options may be useful:
> > CONFIG_DEBUG_MUTEXES=y
> > CONFIG_KASAN=y
> >
> > +BPF testing
> > +-----------
> > +
> > +For BPF related tests:
> > +
> > +.. code-block::
> > +
> > + CONFIG_BPF=y
> > + CONFIG_BPF_JIT=y
> > + CONFIG_CGROUPS=y
> > + CONFIG_CGROUP_BPF=y
> > +
> > +
> > EXAMPLES
> > ========
> >
> > @@ -127,6 +140,15 @@ Running a specific test of mgmt-tester
> >
> > $ tools/test-runner -k /pathto/bzImage -- tools/mgmt-tester -s "<name>"
> >
> > +Compiling and running BPF tests
> > +-------------------------------
> > +
> > +.. code-block::
> > +
> > + $ ./configure --enable-testing --enable-testing-bpf=/home/me/linux/vmlinux
> > + $ make
> > + $ tools/test-runner -k /home/me/linux/arch/x86_64/boot/bzImage -- tools/iso-tester -s BPF
> > +
> > Running bluetoothctl with emulated controller
> > ---------------------------------------------
> >
> > diff --git a/doc/tester.config b/doc/tester.config
> > index 099eddc79..548e4c629 100644
> > --- a/doc/tester.config
> > +++ b/doc/tester.config
> > @@ -57,3 +57,8 @@ CONFIG_PROVE_RCU=y
> > CONFIG_LOCKDEP=y
> > CONFIG_DEBUG_MUTEXES=y
> > CONFIG_KASAN=y
> > +
> > +CONFIG_BPF=y
> > +CONFIG_BPF_JIT=y
> > +CONFIG_CGROUPS=y
> > +CONFIG_CGROUP_BPF=y
> > diff --git a/tools/iso-tester.c b/tools/iso-tester.c
> > index 350775fdd..da164c771 100644
> > --- a/tools/iso-tester.c
> > +++ b/tools/iso-tester.c
> > @@ -517,6 +517,9 @@ struct iso_client_data {
> >
> > /* Disable BT_POLL_ERRQUEUE before enabling TX timestamping */
> > bool no_poll_errqueue;
> > +
> > + /* Enable BPF TX timestamping */
> > + bool bpf_timestamping;
>
> Let's keep it short, bpf_ts.
Ok.
[clip]
> Btw, does BPF also use the error queue? Or better yet can we avoid
> waiting up bluetoothd id the process/pipewire use the BPF mode to be
> notified of packet completion?
BPF timestamping does not use errqueue, so it avoids the wakeup
problem.
It's harder to deploy:
- needs CAP_NET_ADMIN afaik, and to be attached to a cgroup
- BPF part may need recompilation if kernel structs it uses change
(maybe not that often since it's mostly skb_shared_info)
Not so great for sound servers running as user.
--
Pauli Virtanen
