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  1. Feb 21, 2019
  3. Feb 20, 2019
    • Arnaldo Carvalho de Melo's avatar
      perf trace: Allow dumping a BPF map after setting up BPF events · ff7a4f98
      Arnaldo Carvalho de Melo authored 
      Initial use case:

Dumping the maps setup by tools/perf/examples/bpf/augmented_raw_syscalls.c,
which so far are just booleans, showing just non-zeroed entries:

  # cat ~/.perfconfig
  [llvm]
	dump-obj = true
	clang-opt = -g
  [trace]
	#add_events = /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o
	add_events = /wb/augmented_raw_syscalls.o
  $ date
  Tue Feb 19 16:29:33 -03 2019
  $ ls -la /wb/augmented_raw_syscalls.o
  -rwxr-xr-x. 1 root root 14048 Jan 24 12:09 /wb/augmented_raw_syscalls.o
  $ file /wb/augmented_raw_syscalls.o
  /wb/augmented_raw_syscalls.o: ELF 64-bit LSB relocatable, eBPF, version 1 (SYSV), with debug_info, not stripped
  $
  # trace -e recvmmsg,sendmmsg --map-dump foobar
  ERROR: BPF map "foobar" not found
  # trace -e recvmmsg,sendmmsg --map-dump filtered_pids
  ERROR: BPF map "filtered_pids" not found
  # trace -e recvmmsg,sendmmsg --map-dump pids_filtered
  [2583] = 1,
  [2267] = 1,
  ^Z
  [1]+  Stopped                 trace -e recvmmsg,sendmmsg --map-dump pids_filtered
  # pidof trace
  2267
  # ps ax|grep gnome-terminal|grep -v grep
  2583 ?        Ssl   58:33 /usr/libexec/gnome-terminal-server
  ^C
  # trace -e recvmmsg,sendmmsg --map-dump syscalls
  [299] = 1,
  [307] = 1,
  ^C
  # grep x64_recvmmsg arch/x86/entry/syscalls/syscall_64.tbl
  299	64	recvmmsg		__x64_sys_recvmmsg
  # grep x64_sendmmsg arch/x86/entry/syscalls/syscall_64.tbl
  307	64	sendmmsg		__x64_sys_sendmmsg
  #

Next step probably will be something like 'perf stat's --interval-print and
--interval-clear.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Link: https://lkml.kernel.org/n/tip-ztxj25rtx37ixo9cfajt8ocy@git.kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      ff7a4f98
    • Arnaldo Carvalho de Melo's avatar
      perf bpf: Add bpf_map dumper · d19f8564
      Arnaldo Carvalho de Melo authored 
      At some point I'll suggest moving this to libbpf, for now I'll
experiment with ways to dump BPF maps set by events in 'perf trace',
starting with a very basic dumper for the current very limited needs
of the augmented_raw_syscalls code: dumping booleans.

Having functions that apply to the map keys and values and do table
lookup in things like syscall id to string tables should come next.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Link: https://lkml.kernel.org/n/tip-lz14w0esqyt1333aon05jpwc@git.kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      d19f8564
    • Thomas Richter's avatar
      perf test: Fix failure of 'evsel-tp-sched' test on s390 · 03d30971
      Thomas Richter authored 
      Commit 489338a7 ("perf tests evsel-tp-sched: Fix bitwise operator")
causes test case 14 "Parse sched tracepoints fields" to fail on s390.

This test succeeds on x86.

In fact this test now fails on all architectures with type char treated
as type unsigned char.

The root cause is the signed-ness of character arrays in the tracepoints
sched_switch for structure members prev_comm and next_comm.

On s390 the output of:

 [root@m35lp76 perf]# cat /sys/kernel/debug/tracing/events/sched/sched_switch/format
 name: sched_switch
 ID: 287
 format:
   field:unsigned short common_type; offset:0; size:2;	signed:0;
   ...
   field:char prev_comm[16]; offset:8; size:16;	signed:0;
   ...
   field:char next_comm[16]; offset:40; size:16; signed:0;

reveals the character arrays prev_comm and next_comm are per
default unsigned char and have values in the range of 0..255.

On x86 both fields are signed as this output shows:
 [root@f29]# cat /sys/kernel/debug/tracing/events/sched/sched_switch/format
 name: sched_switch
 ID: 287
 format:
   field:unsigned short common_type; offset:0; size:2;	signed:0;
   ...
   field:char prev_comm[16]; offset:8; size:16;	signed:1;
   ...
   field:char next_comm[16]; offset:40; size:16; signed:1;

and the character arrays prev_comm and next_comm are per default signed
char and have values in the range of -1..127.  The implementation of
type char is architecture specific.

Since the character arrays in both tracepoints sched_switch and
sched_wakeup should contain ascii characters, simply omit the check for
signedness in the test case.

Output before:

  [root@m35lp76 perf]# ./perf test -F 14
  14: Parse sched tracepoints fields                        :
  --- start ---
  sched:sched_switch: "prev_comm" signedness(0) is wrong, should be 1
  sched:sched_switch: "next_comm" signedness(0) is wrong, should be 1
  sched:sched_wakeup: "comm" signedness(0) is wrong, should be 1
  ---- end ----
  14: Parse sched tracepoints fields                        : FAILED!
  [root@m35lp76 perf]#

Output after:

  [root@m35lp76 perf]# ./perf test -Fv 14
  14: Parse sched tracepoints fields                        :
  --- start ---
  ---- end ----
  Parse sched tracepoints fields: Ok
  [root@m35lp76 perf]#

Fixes: 489338a7

 ("perf tests evsel-tp-sched: Fix bitwise operator")

Signed-off-by: default avatarThomas Richter <tmricht@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20190219153639.31267-1-tmricht@linux.ibm.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      03d30971
    • Jonas Rabenstein's avatar
      perf doc: Fix documentation of the Flags section in perf.data · 8c23a522
      Jonas Rabenstein authored 
      

According to the current documentation the flags section is placed after
the file header itself but the code assumes to find the flags section
after the data section. This change updates the documentation to that
assumption.

Signed-off-by: default avatarJonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: http://lkml.kernel.org/r/20190219154515.3954-2-jonas.rabenstein@studium.uni-erlangen.de


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      8c23a522
    • Jonas Rabenstein's avatar
      perf doc: Fix HEADER_CMDLINE description in perf.data documentation · 7a663c0f
      Jonas Rabenstein authored 
      

The content of the HEADER_CMDLINE feature header is a perf_header_string_list
of the argument vector and not a perf_header_string of the commandline.

Signed-off-by: default avatarJonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: http://lkml.kernel.org/r/20190219154515.3954-1-jonas.rabenstein@studium.uni-erlangen.de


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      7a663c0f
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