perf build: Fix installation directory for eBPF
The perf tool build and install is controlled via a Makefile. The
'install' rule creates directories and copies files. Among them are
header files installed in /usr/lib/include/perf/bpf/.
However all listed examples are installing its header files in
/usr/lib/<tool-name>/...[/include]/header.h
and not in
/usr/lib/include/<tool-name>/.../header.h.
Background information:
Building the Fedora 28 glibc RPM on s390x and s390 fails on s390 (gcc
-m31) as gcc is not able to find header-files like stdbool.h.
In the glibc.spec file, you can see that glibc is configured with
"--with-headers". In this case, first -nostdinc is added to the CFLAGS
and then further include paths are added via -isystem. One of those
paths should contain header files like stdbool.h.
In order to get this path, gcc is invoked with:
- on Fedora 28 (with 4.18 kernel):
$ gcc -print-file-name=include
/usr/lib/gcc/s390x-redhat-linux/8/include
$ gcc -m31 -print-file-name=include
/usr/lib/gcc/s390x-redhat-linux/8/../../../../lib/include
=> If perf is installed, this is: /usr/lib/include
On my machine this directory is only containing the directory "perf".
If perf is not installed gcc returns: /usr/lib/gcc/s390x-redhat-linux/8/include
- on Ubuntu 18.04 (with 4.15 kernel):
$ gcc -print-file-name=include
/usr/lib/gcc/s390x-linux-gnu/7/include
$ gcc -m31 -print-file-name=include
/usr/lib/gcc/s390x-linux-gnu/7/include
=> gcc returns the correct path even if perf is installed.
In each case, the introduction of the subdirectory /usr/lib/include
leads to the regression that one can not build the glibc RPM for s390
anymore as gcc can not find headers like stdbool.h.
To remedy this install bpf.h to /usr/lib/perf/include/bpf/bpf.h
Output before using the command 'perf test -Fv 40':
echo '...[bpf-program-source]...' | /usr/bin/clang ... \
-I/root/lib/include/perf/bpf ...
^^^^^^^^^^^^
...
[root@p23lp27 perf]# perf test -F 40
40: BPF filter :
40.1: Basic BPF filtering : Ok
40.2: BPF pinning : Ok
40.3: BPF prologue generation : Ok
40.4: BPF relocation checker : Ok
[root@p23lp27 perf]#
Output after using command 'perf test -Fv 40':
echo '...[bpf-program-source]...' | /usr/bin/clang ... \
-I/root/lib/perf/include/bpf ...
^^^^^^^^^^^^
...
[root@p23lp27 perf]# perf test -F 40
40: BPF filter :
40.1: Basic BPF filtering : Ok
40.2: BPF pinning : Ok
40.3: BPF prologue generation : Ok
40.4: BPF relocation checker : Ok
[root@p23lp27 perf]#
Committer testing:
While the above 'perf test -F 40' (or 'perf test bpf') will allow us
to see that the correct path is now added via -I, to actually test this
we better try to use a bpf script that includes files in the changed
directory.
We have the files that now reside in /root/lib/perf/examples/bpf/ to do
just that:
# tail -8 /root/lib/perf/examples/bpf/5sec.c
#include <bpf.h>
int probe(hrtimer_nanosleep, rqtp->tv_sec)(void *ctx, int err, long sec)
{
return sec == 5;
}
license(GPL);
# perf trace -e *sleep -e /root/lib/perf/examples/bpf/5sec.c sleep 4
0.333 (4000.086 ms): sleep/9248 nanosleep(rqtp: 0x7ffc155f3300) = 0
# perf trace -e *sleep -e /root/lib/perf/examples/bpf/5sec.c sleep 5
0.287 ( ): sleep/9659 nanosleep(rqtp: 0x7ffeafe38200) ...
0.290 ( ): perf_bpf_probe:hrtimer_nanosleep:(ffffffff9911efe0) tv_sec=5
0.287 (5000.059 ms): sleep/9659 ... [continued]: nanosleep()) = 0
# perf trace -e *sleep -e /root/lib/perf/examples/bpf/5sec.c sleep 6
0.247 (5999.951 ms): sleep/10068 nanosleep(rqtp: 0x7fff2086d900) = 0
# perf trace -e *sleep -e /root/lib/perf/examples/bpf/5sec.c sleep 5.987
0.293 ( ): sleep/10489 nanosleep(rqtp: 0x7ffdd4fc10e0) ...
0.296 ( ): perf_bpf_probe:hrtimer_nanosleep:(ffffffff9911efe0) tv_sec=5
0.293 (5986.912 ms): sleep/10489 ... [continued]: nanosleep()) = 0
#
Suggested-by: Stefan Liebler <stli@linux.ibm.com>
Suggested-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Fixes: 1b16fffa389d ("perf llvm-utils: Add bpf include path to clang command line")
Link: http://lkml.kernel.org/r/20180731073254.91090-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
1 file changed