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authorArnaldo Carvalho de Melo <acme@redhat.com>2010-01-05 16:50:31 -0200
committerIngo Molnar <mingo@elte.hu>2010-01-13 10:09:11 +0100
commit56b03f3c4d641dbdbce2e52a2969712e85b0e030 (patch)
tree3c15eb7ed163ca63bed395b233535f6fca2cccec /tools/perf/util/event.h
parentb9a63b9b56d6910a25e3d4905525aef150420a9b (diff)
perf tools: Handle relocatable kernels
DSOs don't have this problem because the kernel emits a PERF_MMAP for each new executable mapping it performs on monitored threads. To fix the kernel case we simulate the same behaviour, by having 'perf record' to synthesize a PERF_MMAP for the kernel, encoded like this: [root@doppio ~]# perf record -a -f sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.344 MB perf.data (~15038 samples) ] [root@doppio ~]# perf report -D | head -10 0xd0 [0x40]: event: 1 . . ... raw event: size 64 bytes . 0000: 01 00 00 00 00 00 40 00 00 00 00 00 00 00 00 00 ......@........ . 0010: 00 00 00 81 ff ff ff ff 00 00 00 00 00 00 00 00 ............... . 0020: 00 00 00 00 00 00 00 00 5b 6b 65 72 6e 65 6c 2e ........ [kernel . 0030: 6b 61 6c 6c 73 79 6d 73 2e 5f 74 65 78 74 5d 00 kallsyms._text] . 0xd0 [0x40]: PERF_RECORD_MMAP 0/0: [0xffffffff81000000((nil)) @ (nil)]: [kernel.kallsyms._text] I.e. we identify such event as having: .pid = 0 .filename = [kernel.kallsyms.REFNAME] .start = REFNAME addr in /proc/kallsyms at 'perf record' time and use now a hardcoded value of '.text' for REFNAME. Then, later, in 'perf report', if there are any kernel hits and thus we need to resolve kernel symbols, we search for REFNAME and if its address changed, relocation happened and we thus must change the kernel mapping routines to one that uses .pgoff as the relocation to apply. This way we use the same mechanism used for the other DSOs and don't have to do a two pass in all the kernel symbols. Reported-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> LKML-Reference: <1262717431-1246-1-git-send-email-acme@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'tools/perf/util/event.h')
-rw-r--r--tools/perf/util/event.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 80fb3653c80..61fc0dc658c 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -110,6 +110,10 @@ int event__synthesize_thread(pid_t pid,
void event__synthesize_threads(int (*process)(event_t *event,
struct perf_session *session),
struct perf_session *session);
+int event__synthesize_kernel_mmap(int (*process)(event_t *event,
+ struct perf_session *session),
+ struct perf_session *session,
+ const char *symbol_name);
int event__process_comm(event_t *self, struct perf_session *session);
int event__process_lost(event_t *self, struct perf_session *session);