From: Adrian Hunter <adrian.hun...@intel.com> Make the "object code reading" test attempt to read from kcore.
The test uses objdump which struggles with kcore. i.e. doesn't always work, sometimes takes a long time. The test has been made to work around those issues. Signed-off-by: Adrian Hunter <adrian.hun...@intel.com> Cc: David Ahern <dsah...@gmail.com> Cc: Frederic Weisbecker <fweis...@gmail.com> Cc: Ingo Molnar <mi...@kernel.org> Cc: Jiri Olsa <jo...@redhat.com> Cc: Mike Galbraith <efa...@gmx.de> Cc: Namhyung Kim <namhy...@gmail.com> Cc: Paul Mackerras <pau...@samba.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Stephane Eranian <eran...@google.com> Link: http://lkml.kernel.org/r/1375875537-4509-10-git-send-email-adrian.hun...@intel.com Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/tests/code-reading.c | 100 ++++++++++++++++++++++++++++++++-------- 1 file changed, 82 insertions(+), 18 deletions(-) diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c index 0c7b052..8e0943b 100644 --- a/tools/perf/tests/code-reading.c +++ b/tools/perf/tests/code-reading.c @@ -20,6 +20,11 @@ #define BUFSZ 1024 #define READLEN 128 +struct state { + u64 done[1024]; + size_t done_cnt; +}; + static unsigned int hex(char c) { if (c >= '0' && c <= '9') @@ -107,6 +112,9 @@ static int read_via_objdump(const char *filename, u64 addr, void *buf, pr_debug("Objdump command is: %s\n", cmd); + /* Ignore objdump errors */ + strcat(cmd, " 2>/dev/null"); + f = popen(cmd, "r"); if (!f) { pr_debug("popen failed\n"); @@ -126,7 +134,8 @@ static int read_via_objdump(const char *filename, u64 addr, void *buf, } static int read_object_code(u64 addr, size_t len, u8 cpumode, - struct thread *thread, struct machine *machine) + struct thread *thread, struct machine *machine, + struct state *state) { struct addr_location al; unsigned char buf1[BUFSZ]; @@ -146,7 +155,8 @@ static int read_object_code(u64 addr, size_t len, u8 cpumode, pr_debug("File is: %s\n", al.map->dso->long_name); - if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS) { + if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS && + !dso__is_kcore(al.map->dso)) { pr_debug("Unexpected kernel address - skipping\n"); return 0; } @@ -175,6 +185,24 @@ static int read_object_code(u64 addr, size_t len, u8 cpumode, if (map__load(al.map, NULL)) return -1; + /* objdump struggles with kcore - try each map only once */ + if (dso__is_kcore(al.map->dso)) { + size_t d; + + for (d = 0; d < state->done_cnt; d++) { + if (state->done[d] == al.map->start) { + pr_debug("kcore map tested already"); + pr_debug(" - skipping\n"); + return 0; + } + } + if (state->done_cnt >= ARRAY_SIZE(state->done)) { + pr_debug("Too many kcore maps - skipping\n"); + return 0; + } + state->done[state->done_cnt++] = al.map->start; + } + /* Read the object code using objdump */ objdump_addr = map__rip_2objdump(al.map, al.addr); ret = read_via_objdump(al.map->dso->long_name, objdump_addr, buf2, len); @@ -186,10 +214,19 @@ static int read_object_code(u64 addr, size_t len, u8 cpumode, if (cpumode == PERF_RECORD_MISC_KERNEL || cpumode == PERF_RECORD_MISC_GUEST_KERNEL) { len -= ret; - if (len) + if (len) { pr_debug("Reducing len to %zu\n", len); - else + } else if (dso__is_kcore(al.map->dso)) { + /* + * objdump cannot handle very large segments + * that may be found in kcore. + */ + pr_debug("objdump failed for kcore"); + pr_debug(" - skipping\n"); + return 0; + } else { return -1; + } } } if (ret < 0) { @@ -209,7 +246,7 @@ static int read_object_code(u64 addr, size_t len, u8 cpumode, static int process_sample_event(struct machine *machine, struct perf_evlist *evlist, - union perf_event *event) + union perf_event *event, struct state *state) { struct perf_sample sample; struct thread *thread; @@ -228,14 +265,15 @@ static int process_sample_event(struct machine *machine, cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK; - return read_object_code(sample.ip, READLEN, cpumode, thread, machine); + return read_object_code(sample.ip, READLEN, cpumode, thread, machine, + state); } static int process_event(struct machine *machine, struct perf_evlist *evlist, - union perf_event *event) + union perf_event *event, struct state *state) { if (event->header.type == PERF_RECORD_SAMPLE) - return process_sample_event(machine, evlist, event); + return process_sample_event(machine, evlist, event, state); if (event->header.type < PERF_RECORD_MAX) return machine__process_event(machine, event); @@ -243,14 +281,15 @@ static int process_event(struct machine *machine, struct perf_evlist *evlist, return 0; } -static int process_events(struct machine *machine, struct perf_evlist *evlist) +static int process_events(struct machine *machine, struct perf_evlist *evlist, + struct state *state) { union perf_event *event; int i, ret; for (i = 0; i < evlist->nr_mmaps; i++) { while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) { - ret = process_event(machine, evlist, event); + ret = process_event(machine, evlist, event, state); if (ret < 0) return ret; } @@ -331,10 +370,12 @@ static void do_something(void) enum { TEST_CODE_READING_OK, TEST_CODE_READING_NO_VMLINUX, + TEST_CODE_READING_NO_KCORE, TEST_CODE_READING_NO_ACCESS, + TEST_CODE_READING_NO_KERNEL_OBJ, }; -static int do_test_code_reading(void) +static int do_test_code_reading(bool try_kcore) { struct machines machines; struct machine *machine; @@ -348,6 +389,9 @@ static int do_test_code_reading(void) .uses_mmap = true, }, }; + struct state state = { + .done_cnt = 0, + }; struct thread_map *threads = NULL; struct cpu_map *cpus = NULL; struct perf_evlist *evlist = NULL; @@ -355,7 +399,7 @@ static int do_test_code_reading(void) int err = -1, ret; pid_t pid; struct map *map; - bool have_vmlinux, excl_kernel = false; + bool have_vmlinux, have_kcore, excl_kernel = false; pid = getpid(); @@ -368,6 +412,10 @@ static int do_test_code_reading(void) goto out_err; } + /* Force the use of kallsyms instead of vmlinux to try kcore */ + if (try_kcore) + symbol_conf.kallsyms_name = "/proc/kallsyms"; + /* Load kernel map */ map = machine->vmlinux_maps[MAP__FUNCTION]; ret = map__load(map, NULL); @@ -375,9 +423,15 @@ static int do_test_code_reading(void) pr_debug("map__load failed\n"); goto out_err; } - have_vmlinux = map->dso->symtab_type == DSO_BINARY_TYPE__VMLINUX; - /* No point getting kernel events if there is no vmlinux */ - if (!have_vmlinux) + have_vmlinux = dso__is_vmlinux(map->dso); + have_kcore = dso__is_kcore(map->dso); + + /* 2nd time through we just try kcore */ + if (try_kcore && !have_kcore) + return TEST_CODE_READING_NO_KCORE; + + /* No point getting kernel events if there is no kernel object */ + if (!have_vmlinux && !have_kcore) excl_kernel = true; threads = thread_map__new_by_tid(pid); @@ -461,11 +515,13 @@ static int do_test_code_reading(void) perf_evlist__disable(evlist); - ret = process_events(machine, evlist); + ret = process_events(machine, evlist, &state); if (ret < 0) goto out_err; - if (!have_vmlinux) + if (!have_vmlinux && !have_kcore && !try_kcore) + err = TEST_CODE_READING_NO_KERNEL_OBJ; + else if (!have_vmlinux && !try_kcore) err = TEST_CODE_READING_NO_VMLINUX; else if (excl_kernel) err = TEST_CODE_READING_NO_ACCESS; @@ -492,7 +548,9 @@ int test__code_reading(void) { int ret; - ret = do_test_code_reading(); + ret = do_test_code_reading(false); + if (!ret) + ret = do_test_code_reading(true); switch (ret) { case TEST_CODE_READING_OK: @@ -500,9 +558,15 @@ int test__code_reading(void) case TEST_CODE_READING_NO_VMLINUX: fprintf(stderr, " (no vmlinux)"); return 0; + case TEST_CODE_READING_NO_KCORE: + fprintf(stderr, " (no kcore)"); + return 0; case TEST_CODE_READING_NO_ACCESS: fprintf(stderr, " (no access)"); return 0; + case TEST_CODE_READING_NO_KERNEL_OBJ: + fprintf(stderr, " (no kernel obj)"); + return 0; default: return -1; }; -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/