From dc38218e8b598a0092dae9715e603e9628203bec Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Sun, 11 Oct 2015 17:17:24 -0300 Subject: [PATCH] perf symbols: Try the .debug/ DSO cache as a last resort Not as the first attempt at finding a vmlinux for the running kernel, this way we get a more informative filename to present in tools, it will check that the build-id is the same as the one previously loaded in the DSO in dso->build_id, reading from /sys/kernel/notes, for instance. E.g. in the annotation TUI, going from 'perf top', for the scsi_sg_alloc kernel function, in the first line: Before: scsi_sg_alloc /root/.debug/.build-id/28/2777c262e6b3c0451375163c9a81c893218ab1 After: scsi_sg_alloc /lib/modules/4.3.0-rc1+/build/vmlinux And: # ls -la /root/.debug/.build-id/28/2777c262e6b3c0451375163c9a81c893218ab1 lrwxrwxrwx. 1 root root 81 Sep 22 16:11 /root/.debug/.build-id/28/2777c262e6b3c0451375163c9a81c893218ab1 -> ../../home/git/build/v4.3.0-rc1+/vmlinux/282777c262e6b3c0451375163c9a81c893218ab1 # file ~/.debug/home/git/build/v4.3.0-rc1+/vmlinux/282777c262e6b3c0451375163c9a81c893218ab1 /root/.debug/home/git/build/v4.3.0-rc1+/vmlinux/282777c262e6b3c0451375163c9a81c893218ab1: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, BuildID[sha1]=282777c262e6b3c0451375163c9a81c893218ab1, not stripped # The same as: # file /lib/modules/4.3.0-rc1+/build/vmlinux /lib/modules/4.3.0-rc1+/build/vmlinux: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, BuildID[sha1]=282777c262e6b3c0451375163c9a81c893218ab1, not stripped Furthermore: # sha256sum /lib/modules/4.3.0-rc1+/build/vmlinux e7a789bbdc61029ec09140c228e1dd651271f38ef0b8416c0b7d5ff727b98be2 /lib/modules/4.3.0-rc1+/build/vmlinux # sha256sum ~/.debug/home/git/build/v4.3.0-rc1+/vmlinux/282777c262e6b3c0451375163c9a81c893218ab1 e7a789bbdc61029ec09140c228e1dd651271f38ef0b8416c0b7d5ff727b98be2 /root/.debug/home/git/build/v4.3.0-rc1+/vmlinux/282777c262e6b3c0451375163c9a81c893218ab1 [root@zoo new]# Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Namhyung Kim Cc: Stephane Eranian Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-9y42ikzq3jisiddoi6f07n8z@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/symbol.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index bcda43bee4d4..e7bf0c46918d 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -1607,6 +1607,15 @@ int dso__load_vmlinux_path(struct dso *dso, struct map *map, int i, err = 0; char *filename = NULL; + pr_debug("Looking at the vmlinux_path (%d entries long)\n", + vmlinux_path__nr_entries + 1); + + for (i = 0; i < vmlinux_path__nr_entries; ++i) { + err = dso__load_vmlinux(dso, map, vmlinux_path[i], false, filter); + if (err > 0) + goto out; + } + if (!symbol_conf.ignore_vmlinux_buildid) filename = dso__build_id_filename(dso, NULL, 0); if (filename != NULL) { @@ -1615,15 +1624,6 @@ int dso__load_vmlinux_path(struct dso *dso, struct map *map, goto out; free(filename); } - - pr_debug("Looking at the vmlinux_path (%d entries long)\n", - vmlinux_path__nr_entries + 1); - - for (i = 0; i < vmlinux_path__nr_entries; ++i) { - err = dso__load_vmlinux(dso, map, vmlinux_path[i], false, filter); - if (err > 0) - break; - } out: return err; } -- 2.34.1