perf unwind: Do not look just at the global callchain_param.record_mode

When setting up DWARF callchains on specific events, without using
'record' or 'trace' --call-graph, but instead doing it like:

	perf trace -e cycles/call-graph=dwarf/

The unwind__prepare_access() call in thread__insert_map() when we
process PERF_RECORD_MMAP(2) metadata events were not being performed,
precluding us from using per-event DWARF callchains, handling them just
when we asked for all events to be DWARF, using "--call-graph dwarf".

We do it in the PERF_RECORD_MMAP because we have to look at one of the
executable maps to figure out the executable type (64-bit, 32-bit) of
the DSO laid out in that mmap. Also to look at the architecture where
the perf.data file was recorded.

All this probably should be deferred to when we process a sample for
some thread that has callchains, so that we do this processing only for
the threads with samples, not for all of them.

For now, fix using DWARF on specific events.

Before:

  # perf trace --no-syscalls -e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1
  PING ::1(::1) 56 data bytes
  64 bytes from ::1: icmp_seq=1 ttl=64 time=0.048 ms

  --- ::1 ping statistics ---
  1 packets transmitted, 1 received, 0% packet loss, time 0ms
  rtt min/avg/max/mdev = 0.048/0.048/0.048/0.000 ms
     0.000 probe_libc:inet_pton:(7fe9597bb350))
  Problem processing probe_libc:inet_pton callchain, skipping...
  #

After:

  # perf trace --no-syscalls -e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1
  PING ::1(::1) 56 data bytes
  64 bytes from ::1: icmp_seq=1 ttl=64 time=0.060 ms

  --- ::1 ping statistics ---
  1 packets transmitted, 1 received, 0% packet loss, time 0ms
  rtt min/avg/max/mdev = 0.060/0.060/0.060/0.000 ms
       0.000 probe_libc:inet_pton:(7fd4aa930350))
                                         __inet_pton (inlined)
                                         gaih_inet.constprop.7 (/usr/lib64/libc-2.26.so)
                                         __GI_getaddrinfo (inlined)
                                         [0xffffaa804e51af3f] (/usr/bin/ping)
                                         __libc_start_main (/usr/lib64/libc-2.26.so)
                                         [0xffffaa804e51b379] (/usr/bin/ping)
  #
  # perf trace --call-graph=dwarf --no-syscalls -e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1
  PING ::1(::1) 56 data bytes
  64 bytes from ::1: icmp_seq=1 ttl=64 time=0.057 ms

  --- ::1 ping statistics ---
  1 packets transmitted, 1 received, 0% packet loss, time 0ms
  rtt min/avg/max/mdev = 0.057/0.057/0.057/0.000 ms
       0.000 probe_libc:inet_pton:(7f9363b9e350))
                                         __inet_pton (inlined)
                                         gaih_inet.constprop.7 (/usr/lib64/libc-2.26.so)
                                         __GI_getaddrinfo (inlined)
                                         [0xffffa9e8a14e0f3f] (/usr/bin/ping)
                                         __libc_start_main (/usr/lib64/libc-2.26.so)
                                         [0xffffa9e8a14e1379] (/usr/bin/ping)
  #
  # perf trace --call-graph=fp --no-syscalls -e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1
  PING ::1(::1) 56 data bytes
  64 bytes from ::1: icmp_seq=1 ttl=64 time=0.077 ms

  --- ::1 ping statistics ---
  1 packets transmitted, 1 received, 0% packet loss, time 0ms
  rtt min/avg/max/mdev = 0.077/0.077/0.077/0.000 ms
       0.000 probe_libc:inet_pton:(7f4947e1c350))
                                         __inet_pton (inlined)
                                         gaih_inet.constprop.7 (/usr/lib64/libc-2.26.so)
                                         __GI_getaddrinfo (inlined)
                                         [0xffffaa716d88ef3f] (/usr/bin/ping)
                                         __libc_start_main (/usr/lib64/libc-2.26.so)
                                         [0xffffaa716d88f379] (/usr/bin/ping)
  #
  # perf trace --no-syscalls -e probe_libc:inet_pton/call-graph=fp/ ping -6 -c 1 ::1
  PING ::1(::1) 56 data bytes
  64 bytes from ::1: icmp_seq=1 ttl=64 time=0.078 ms

  --- ::1 ping statistics ---
  1 packets transmitted, 1 received, 0% packet loss, time 0ms
  rtt min/avg/max/mdev = 0.078/0.078/0.078/0.000 ms
       0.000 probe_libc:inet_pton:(7fa157696350))
                                         __GI___inet_pton (/usr/lib64/libc-2.26.so)
                                         getaddrinfo (/usr/lib64/libc-2.26.so)
                                         [0xffffa9ba39c74f40] (/usr/bin/ping)
  #

Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Hendrick Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Thomas Richter <tmricht@linux.vnet.ibm.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/r/20180116182650.GE16107@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index c0debc3f79b6e25efbd01176b72c84caa0ff7cfd..c0815a37fdb5a357615be3da2df2fffe62b25222 100644 (file)
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -2390,9 +2390,10 @@ static int setup_callchain(struct perf_evlist *evlist)
        enum perf_call_graph_mode mode = CALLCHAIN_NONE;
 
        if ((sample_type & PERF_SAMPLE_REGS_USER) &&
-           (sample_type & PERF_SAMPLE_STACK_USER))
+           (sample_type & PERF_SAMPLE_STACK_USER)) {
                mode = CALLCHAIN_DWARF;
-       else if (sample_type & PERF_SAMPLE_BRANCH_STACK)
+               dwarf_callchain_users = true;
+       } else if (sample_type & PERF_SAMPLE_BRANCH_STACK)
                mode = CALLCHAIN_LBR;
        else if (sample_type & PERF_SAMPLE_CALLCHAIN)
                mode = CALLCHAIN_FP;

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index dd4df9a5cd0611a81e6052b21d3e6b64647e0fbf..6593779224d5c763e5e22934c22f9355b6ed1354 100644 (file)
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -338,9 +338,10 @@ static int report__setup_sample_type(struct report *rep)
 
        if (symbol_conf.use_callchain || symbol_conf.cumulate_callchain) {
                if ((sample_type & PERF_SAMPLE_REGS_USER) &&
-                   (sample_type & PERF_SAMPLE_STACK_USER))
+                   (sample_type & PERF_SAMPLE_STACK_USER)) {
                        callchain_param.record_mode = CALLCHAIN_DWARF;
-               else if (sample_type & PERF_SAMPLE_BRANCH_STACK)
+                       dwarf_callchain_users = true;
+               } else if (sample_type & PERF_SAMPLE_BRANCH_STACK)
                        callchain_param.record_mode = CALLCHAIN_LBR;
                else
                        callchain_param.record_mode = CALLCHAIN_FP;

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index c1cce474c0f105f0041f7cf2931877f1a167ca5c..08bc818f371b8858a63cbc47fb72f1377ee64aad 100644 (file)
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -2919,9 +2919,10 @@ static void script__setup_sample_type(struct perf_script *script)
 
        if (symbol_conf.use_callchain || symbol_conf.cumulate_callchain) {
                if ((sample_type & PERF_SAMPLE_REGS_USER) &&
-                   (sample_type & PERF_SAMPLE_STACK_USER))
+                   (sample_type & PERF_SAMPLE_STACK_USER)) {
                        callchain_param.record_mode = CALLCHAIN_DWARF;
-               else if (sample_type & PERF_SAMPLE_BRANCH_STACK)
+                       dwarf_callchain_users = true;
+               } else if (sample_type & PERF_SAMPLE_BRANCH_STACK)
                        callchain_param.record_mode = CALLCHAIN_LBR;
                else
                        callchain_param.record_mode = CALLCHAIN_FP;

diff --git a/tools/perf/tests/dwarf-unwind.c b/tools/perf/tests/dwarf-unwind.c
index ac40e05bcab4292d52f971ad02c1c2857d049d6f..260418969120fd2c4d2eff6ab3742539589c8d9c 100644 (file)
--- a/tools/perf/tests/dwarf-unwind.c
+++ b/tools/perf/tests/dwarf-unwind.c
@@ -173,6 +173,7 @@ int test__dwarf_unwind(struct test *test __maybe_unused, int subtest __maybe_unu
        }
 
        callchain_param.record_mode = CALLCHAIN_DWARF;
+       dwarf_callchain_users = true;
 
        if (init_live_machine(machine)) {
                pr_err("Could not init machine\n");

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 082505d08d720b18cae0051591b087bb86e6e456..32ef7bdca1cf8cbf6e29cb6e5bbe8220230bf569 100644 (file)
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -37,6 +37,15 @@ struct callchain_param callchain_param = {
        CALLCHAIN_PARAM_DEFAULT
 };
 
+/*
+ * Are there any events usind DWARF callchains?
+ *
+ * I.e.
+ *
+ * -e cycles/call-graph=dwarf/
+ */
+bool dwarf_callchain_users;
+
 struct callchain_param callchain_param_default = {
        CALLCHAIN_PARAM_DEFAULT
 };
@@ -265,6 +274,7 @@ int parse_callchain_record(const char *arg, struct callchain_param *param)
                        ret = 0;
                        param->record_mode = CALLCHAIN_DWARF;
                        param->dump_size = default_stack_dump_size;
+                       dwarf_callchain_users = true;
 
                        tok = strtok_r(NULL, ",", &saveptr);
                        if (tok) {

diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index b79ef2478a575fd206e52cf4860f49230ae64930..154560b1eb653c42f722b291308313b6c675cc7f 100644 (file)
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -89,6 +89,8 @@ enum chain_value {
        CCVAL_COUNT,
 };
 
+extern bool dwarf_callchain_users;
+
 struct callchain_param {
        bool                    enabled;
        enum perf_call_graph_mode record_mode;

diff --git a/tools/perf/util/unwind-libunwind-local.c b/tools/perf/util/unwind-libunwind-local.c
index 7a42f703e858b7830bcfde8dd69d0bbe71764dd3..af873044d33a234e3f4237cda3d8f90943534a9b 100644 (file)
--- a/tools/perf/util/unwind-libunwind-local.c
+++ b/tools/perf/util/unwind-libunwind-local.c
@@ -631,9 +631,8 @@ static unw_accessors_t accessors = {
 
 static int _unwind__prepare_access(struct thread *thread)
 {
-       if (callchain_param.record_mode != CALLCHAIN_DWARF)
+       if (!dwarf_callchain_users)
                return 0;
-
        thread->addr_space = unw_create_addr_space(&accessors, 0);
        if (!thread->addr_space) {
                pr_err("unwind: Can't create unwind address space.\n");
@@ -646,17 +645,15 @@ static int _unwind__prepare_access(struct thread *thread)
 
 static void _unwind__flush_access(struct thread *thread)
 {
-       if (callchain_param.record_mode != CALLCHAIN_DWARF)
+       if (!dwarf_callchain_users)
                return;
-
        unw_flush_cache(thread->addr_space, 0, 0);
 }
 
 static void _unwind__finish_access(struct thread *thread)
 {
-       if (callchain_param.record_mode != CALLCHAIN_DWARF)
+       if (!dwarf_callchain_users)
                return;
-
        unw_destroy_addr_space(thread->addr_space);
 }