perf intel-pt: Add PSB events

Emitting a PSB+ can cause a CPU a slight delay. When doing timing analysis
of code with Intel PT, it is useful to know if a timing bubble was caused
by Intel PT or not. Add reporting of PSB events via perf script. PSB
events are printed with the existing itrace 'p' option which also prints
power and frequency changes. The PSB event contains the trace offset at
which the PSB occurs, to allow easy reference back to the PSB+ packets.

The PSB event timestamp is always the timestamp from the PSB+ TSC
packet, and the ip is always the address from the PSB+ FUP packet.

The code changes are non-trivial because the decoder must walk to the
PSB+ FUP address before outputting the PSB event.

Example:

  $ perf record -e intel_pt/cyc,psb_period=0/u uname
  Linux
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.046 MB perf.data ]
  $ perf script --itrace=p --ns
     perf 17981 [006] 25617.510820383:  psb:  psb offs: 0                               0 [unknown] ([unknown])
     perf 17981 [006] 25617.510820383:  cbr:  cbr: 42 freq: 4219 MHz (156%)             0 [unknown] ([unknown])
    uname 17981 [006] 25617.510889753:  psb:  psb offs: 0xb50                7f78c12a212e __GI___tunables_init+0xee (/usr/lib/x86_64-linux-gnu/ld-2.31.so)
    uname 17981 [006] 25617.510899162:  psb:  psb offs: 0x12d0               7f78c128af1c dl_main+0x93c (/usr/lib/x86_64-linux-gnu/ld-2.31.so)
    uname 17981 [006] 25617.510939242:  psb:  psb offs: 0x1a50               7f78c128eefc _dl_map_object_from_fd+0x13c (/usr/lib/x86_64-linux-gnu/ld-2.31.so)
    uname 17981 [006] 25617.510981274:  psb:  psb offs: 0x21c8               7f78c1296307 _dl_relocate_object+0x927 (/usr/lib/x86_64-linux-gnu/ld-2.31.so)
    uname 17981 [006] 25617.510993034:  psb:  psb offs: 0x2948               7f78c12940e4 _dl_lookup_symbol_x+0x14 (/usr/lib/x86_64-linux-gnu/ld-2.31.so)
    uname 17981 [006] 25617.511003871:  psb:  psb offs: 0x30c8               7f78c12937b3 do_lookup_x+0x2f3 (/usr/lib/x86_64-linux-gnu/ld-2.31.so)
    uname 17981 [006] 25617.511019854:  psb:  psb offs: 0x3850               7f78c1295eed _dl_relocate_object+0x50d (/usr/lib/x86_64-linux-gnu/ld-2.31.so)
    uname 17981 [006] 25617.511029015:  psb:  psb offs: 0x4390               7f78c12a855a strcmp+0xf6a (/usr/lib/x86_64-linux-gnu/ld-2.31.so)
    uname 17981 [006] 25617.511064876:  psb:  psb offs: 0x4b10                          0 [unknown] ([unknown])
    uname 17981 [006] 25617.511080762:  psb:  psb offs: 0x5290               7f78c11db53d _dl_addr+0x13d (/usr/lib/x86_64-linux-gnu/libc-2.31.so)
    uname 17981 [006] 25617.511086035:  psb:  psb offs: 0x5a08               7f78c11db538 _dl_addr+0x138 (/usr/lib/x86_64-linux-gnu/libc-2.31.so)
    uname 17981 [006] 25617.511091381:  psb:  psb offs: 0x6190               7f78c11db534 _dl_addr+0x134 (/usr/lib/x86_64-linux-gnu/libc-2.31.so)
    uname 17981 [006] 25617.511096681:  psb:  psb offs: 0x6910               7f78c11db4c3 _dl_addr+0xc3 (/usr/lib/x86_64-linux-gnu/libc-2.31.so)
    uname 17981 [006] 25617.511119520:  psb:  psb offs: 0x7090               7f78c10ada5e _nl_intern_locale_data+0x12e (/usr/lib/x86_64-linux-gnu/libc-2.31.so)
    uname 17981 [006] 25617.511126584:  psb:  psb offs: 0x7818               7f78c10ada50 _nl_intern_locale_data+0x120 (/usr/lib/x86_64-linux-gnu/libc-2.31.so)
    uname 17981 [006] 25617.511132775:  psb:  psb offs: 0x8358               7f78c10c20c0 getenv+0xa0 (/usr/lib/x86_64-linux-gnu/libc-2.31.so)
    uname 17981 [006] 25617.511134598:  psb:  psb offs: 0x8ad0               7f78c10ada09 _nl_intern_locale_data+0xd9 (/usr/lib/x86_64-linux-gnu/libc-2.31.so)
    uname 17981 [006] 25617.511135685:  psb:  psb offs: 0x9258               7f78c10ada50 _nl_intern_locale_data+0x120 (/usr/lib/x86_64-linux-gnu/libc-2.31.so)
    uname 17981 [006] 25617.511138322:  psb:  psb offs: 0x99d0               7f78c11fffd9 __strncmp_avx2+0x39 (/usr/lib/x86_64-linux-gnu/libc-2.31.so)
    uname 17981 [006] 25617.511158907:  psb:  psb offs: 0xa150                          0 [unknown] ([unknown])

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/r/20210205175350.23817-5-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 7 insertions, 2 deletions

diff --git a/tools/perf/Documentation/itrace.txt b/tools/perf/Documentation/itrace.txt
index 079cdfabb352..0f1005209a2b 100644
--- a/tools/perf/Documentation/itrace.txt
+++ b/tools/perf/Documentation/itrace.txt
@@ -4,7 +4,7 @@
 		r	synthesize branches events (returns only)
 		x	synthesize transactions events
 		w	synthesize ptwrite events
-		p	synthesize power events
+		p	synthesize power events (incl. PSB events for Intel PT)
 		o	synthesize other events recorded due to the use
 			of aux-output (refer to perf record)
 		e	synthesize error events
diff --git a/tools/perf/Documentation/perf-intel-pt.txt b/tools/perf/Documentation/perf-intel-pt.txt
index cd362dc2af07..0b8a339803cb 100644
--- a/tools/perf/Documentation/perf-intel-pt.txt
+++ b/tools/perf/Documentation/perf-intel-pt.txt
@@ -858,7 +858,7 @@ The letters are:
 	b	synthesize "branches" events
 	x	synthesize "transactions" events
 	w	synthesize "ptwrite" events
-	p	synthesize "power" events
+	p	synthesize "power" events (incl. PSB events)
 	c	synthesize branches events (calls only)
 	r	synthesize branches events (returns only)
 	e	synthesize tracing error events
@@ -913,6 +913,11 @@ Where:
 For more details refer to the Intel 64 and IA-32 Architectures Software
 Developer Manuals.
 
+PSB events show when a PSB+ occurred and also the byte-offset in the trace.
+Emitting a PSB+ can cause a CPU a slight delay. When doing timing analysis
+of code with Intel PT, it is useful to know if a timing bubble was caused
+by Intel PT or not.
+
 Error events show where the decoder lost the trace.  Error events
 are quite important.  Users must know if what they are seeing is a complete
 picture or not. The "e" option may be followed by flags which affect what errors