![Arnaldo Carvalho de Melo](/assets/img/avatar_default.png)
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>
73 lines
1.7 KiB
C
73 lines
1.7 KiB
C
#ifndef __PERF_SESSION_H
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#define __PERF_SESSION_H
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#include "event.h"
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#include "header.h"
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#include "thread.h"
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#include <linux/rbtree.h>
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#include "../../../include/linux/perf_event.h"
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struct ip_callchain;
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struct thread;
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struct symbol;
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struct perf_session {
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struct perf_header header;
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unsigned long size;
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unsigned long mmap_window;
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struct map_groups kmaps;
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struct rb_root threads;
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struct thread *last_match;
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struct map *vmlinux_maps[MAP__NR_TYPES];
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struct events_stats events_stats;
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unsigned long event_total[PERF_RECORD_MAX];
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unsigned long unknown_events;
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struct rb_root hists;
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u64 sample_type;
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struct {
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const char *name;
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u64 addr;
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} ref_reloc_sym;
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int fd;
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int cwdlen;
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char *cwd;
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char filename[0];
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};
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typedef int (*event_op)(event_t *self, struct perf_session *session);
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struct perf_event_ops {
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event_op sample,
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mmap,
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comm,
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fork,
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exit,
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lost,
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read,
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throttle,
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unthrottle;
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};
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struct perf_session *perf_session__new(const char *filename, int mode, bool force);
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void perf_session__delete(struct perf_session *self);
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int perf_session__process_events(struct perf_session *self,
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struct perf_event_ops *event_ops);
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struct symbol **perf_session__resolve_callchain(struct perf_session *self,
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struct thread *thread,
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struct ip_callchain *chain,
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struct symbol **parent);
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bool perf_session__has_traces(struct perf_session *self, const char *msg);
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int perf_header__read_build_ids(int input, u64 offset, u64 file_size);
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int perf_session__set_kallsyms_ref_reloc_sym(struct perf_session *self,
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const char *symbol_name,
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u64 addr);
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void perf_session__reloc_vmlinux_maps(struct perf_session *self,
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u64 unrelocated_addr);
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#endif /* __PERF_SESSION_H */
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