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perf script: Show correct offsets for DWARF-based unwinding
When perf/data is recorded with the dwarf call-graph option, the callchain shown by 'perf script' still shows the binary offsets of the userspace symbols instead of their virtual addresses. Since the symbol offset calculation is based on using virtual address as the ip, we see incorrect offsets as well. The use of virtual addresses affects the ability to find out the line number in the corresponding source file to which an address maps to as described in commit6754075915
("perf unwind: Use addr_location::addr instead of ip for entries"). This has also been addressed by temporarily converting the virtual address to the correponding binary offset so that it can be mapped to the source line number correctly. This is a follow-up for commit1961018469
("perf script: Show virtual addresses instead of offsets"). This can be verified on a powerpc64le system running Fedora 27 as shown below: # perf probe -x /usr/lib64/libc-2.26.so -a inet_pton # perf record -e probe_libc:inet_pton --call-graph=dwarf ping -6 -c 1 ::1 Before: # perf report --stdio --no-children -s sym,srcline -g address # Samples: 1 of event 'probe_libc:inet_pton' # Event count (approx.): 1 # # Overhead Symbol Source:Line # ........ .................... ........... # 100.00% [.] __GI___inet_pton inet_pton.c | ---gaih_inet getaddrinfo.c:537 (inlined) __GI_getaddrinfo getaddrinfo.c:2304 (inlined) main ping.c:519 generic_start_main libc-start.c:308 (inlined) __libc_start_main libc-start.c:102 ... # perf script -F comm,ip,sym,symoff,srcline,dso ping 15af28 __GI___inet_pton+0xffff000099160008 (/usr/lib64/libc-2.26.so) libc-2.26.so[ffff80004ca0af28] 10fa53 gaih_inet+0xffff000099160f43 libc-2.26.so[ffff80004c9bfa53] (inlined) 1105b3 __GI_getaddrinfo+0xffff000099160163 libc-2.26.so[ffff80004c9c05b3] (inlined) 2d6f main+0xfffffffd9f1003df (/usr/bin/ping) ping[fffffffecf882d6f] 2369f generic_start_main+0xffff00009916013f libc-2.26.so[ffff80004c8d369f] (inlined) 23897 __libc_start_main+0xffff0000991600b7 (/usr/lib64/libc-2.26.so) libc-2.26.so[ffff80004c8d3897] After: # perf report --stdio --no-children -s sym,srcline -g address # Samples: 1 of event 'probe_libc:inet_pton' # Event count (approx.): 1 # # Overhead Symbol Source:Line # ........ .................... ........... # 100.00% [.] __GI___inet_pton inet_pton.c | ---gaih_inet.constprop.7 getaddrinfo.c:537 getaddrinfo getaddrinfo.c:2304 main ping.c:519 generic_start_main.isra.0 libc-start.c:308 __libc_start_main libc-start.c:102 ... # perf script -F comm,ip,sym,symoff,srcline,dso ping 7fffb38aaf28 __GI___inet_pton+0x8 (/usr/lib64/libc-2.26.so) inet_pton.c:68 7fffb385fa53 gaih_inet.constprop.7+0xf43 (/usr/lib64/libc-2.26.so) getaddrinfo.c:537 7fffb38605b3 getaddrinfo+0x163 (/usr/lib64/libc-2.26.so) getaddrinfo.c:2304 130782d6f main+0x3df (/usr/bin/ping) ping.c:519 7fffb377369f generic_start_main.isra.0+0x13f (/usr/lib64/libc-2.26.so) libc-start.c:308 7fffb3773897 __libc_start_main+0xb7 (/usr/lib64/libc-2.26.so) libc-start.c:102 Signed-off-by: Sandipan Das <sandipan@linux.ibm.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Milian Wolff <milian.wolff@kdab.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Fixes:6754075915
("perf unwind: Use addr_location::addr instead of ip for entries") Link: http://lkml.kernel.org/r/20180703120555.32971-1-sandipan@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
parent
a7f660d657
commit
2a9d5050dc
3 changed files with 10 additions and 3 deletions
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@ -2272,6 +2272,7 @@ static int unwind_entry(struct unwind_entry *entry, void *arg)
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{
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struct callchain_cursor *cursor = arg;
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const char *srcline = NULL;
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u64 addr;
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if (symbol_conf.hide_unresolved && entry->sym == NULL)
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return 0;
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@ -2279,7 +2280,13 @@ static int unwind_entry(struct unwind_entry *entry, void *arg)
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if (append_inlines(cursor, entry->map, entry->sym, entry->ip) == 0)
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return 0;
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srcline = callchain_srcline(entry->map, entry->sym, entry->ip);
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/*
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* Convert entry->ip from a virtual address to an offset in
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* its corresponding binary.
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*/
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addr = map__map_ip(entry->map, entry->ip);
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srcline = callchain_srcline(entry->map, entry->sym, addr);
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return callchain_cursor_append(cursor, entry->ip,
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entry->map, entry->sym,
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false, NULL, 0, 0, 0, srcline);
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@ -77,7 +77,7 @@ static int entry(u64 ip, struct unwind_info *ui)
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if (__report_module(&al, ip, ui))
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return -1;
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e->ip = al.addr;
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e->ip = ip;
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e->map = al.map;
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e->sym = al.sym;
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@ -575,7 +575,7 @@ static int entry(u64 ip, struct thread *thread,
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struct addr_location al;
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e.sym = thread__find_symbol(thread, PERF_RECORD_MISC_USER, ip, &al);
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e.ip = al.addr;
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e.ip = ip;
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e.map = al.map;
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pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
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