On Mon, Mar 30, 2020 at 05:05:34PM -0400, Frank Ch. Eigler wrote:
> Hi -
>
> I was reminded by the thread that debuginfo downloading for perf is
> worth automating more. Since perf uses elfutils, recently-added
> facilities to elfutils 0.178 (2019-11) already allow automated
> downloading from some perf code paths. The following patch [2] builds
> a little bit on that by ensuring that the downloaded debuginfo is
> plopped into the $HOME/.debug/ hierarchy explicitly, and should cover
> a few more code paths. Feel free to take / adapt this code as you
> like.
I think it's a good base, thanks a lot!
I made few comments before reading above,
feel free to post v2, if not we'll take over ;-)
thanks again,
jirka
>
> debuginfod can also do source code downloading on the fly, but the
> perf/util/srccode.c machinery would need buildids passed, and I
> couldn't quickly figure it out. (Sorry, I also couldn't quickly
> figure out the perf testsuite.)
np ;-)
>
> [1] https://sourceware.org/elfutils/Debuginfod.html
>
> [2]
>
> Author: Frank Ch. Eigler <fche@xxxxxxxxxx>
> Date: Mon Mar 30 16:15:47 2020 -0400
>
> perf build-ids: fall back to debuginfod query if debuginfo not found
>
> During a perf-record, use the -ldebuginfod API to query a debuginfod
> server, should the debug data not be found in the usual system
> locations. If successful, the usual $HOME/.debug dir is populated.
>
> Signed-off-by: Frank Ch. Eigler <fche@xxxxxxxxxx>
>
> diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
> index 574c2e0b9d20..51e051858d21 100644
> --- a/tools/build/Makefile.feature
> +++ b/tools/build/Makefile.feature
> @@ -48,6 +48,7 @@ FEATURE_TESTS_BASIC := \
> libelf-gelf_getnote \
> libelf-getshdrstrndx \
> libelf-mmap \
> + libdebuginfod \
we put new feature checks which are not widely spread yet
and not vitaly needed into FEATURE_TESTS_EXTRA and call:
$(call feature_check,libdebuginfod)
before you check the feature
> libnuma \
> numa_num_possible_cpus \
> libperl \
> @@ -114,6 +115,7 @@ FEATURE_DISPLAY ?= \
> libbfd \
> libcap \
> libelf \
> + libdebuginfod \
I dont see the libdebuginfod.c, did you forget to add it?
> libnuma \
> numa_num_possible_cpus \
> libperl \
> diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
> index 7ac0d8088565..1109f5ec96f7 100644
> --- a/tools/build/feature/Makefile
> +++ b/tools/build/feature/Makefile
> @@ -26,6 +26,7 @@ FILES= \
> test-libelf-gelf_getnote.bin \
> test-libelf-getshdrstrndx.bin \
> test-libelf-mmap.bin \
> + test-libdebuginfod.bin \
> test-libnuma.bin \
> test-numa_num_possible_cpus.bin \
> test-libperl.bin \
> @@ -155,6 +156,9 @@ endif
> $(OUTPUT)test-libelf-getshdrstrndx.bin:
> $(BUILD) -lelf
>
> +$(OUTPUT)test-libdebuginfod.bin:
> + $(BUILD) -ldebuginfod
> +
> $(OUTPUT)test-libnuma.bin:
> $(BUILD) -lnuma
>
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index 80e55e796be9..15eeecf4ff17 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -467,6 +467,11 @@ ifndef NO_LIBELF
> CFLAGS += -DHAVE_ELF_GETSHDRSTRNDX_SUPPORT
> endif
>
> + ifeq ($(feature-libdebuginfod), 1)
> + CFLAGS += -DHAVE_DEBUGINFOD_SUPPORT
> + EXTLIBS += -ldebuginfod
> + endif
> +
> ifndef NO_DWARF
> ifeq ($(origin PERF_HAVE_DWARF_REGS), undefined)
> msg := $(warning DWARF register mappings have not been defined for architecture $(SRCARCH), DWARF support disabled);
> diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
> index c076fc7fe025..a33d00837d81 100644
> --- a/tools/perf/util/build-id.c
> +++ b/tools/perf/util/build-id.c
> @@ -31,6 +31,10 @@
> #include "probe-file.h"
> #include "strlist.h"
>
> +#if HAVE_DEBUGINFOD_SUPPORT
s/if/ifdef
> +#include <elfutils/debuginfod.h>
> +#endif
> +
> #include <linux/ctype.h>
> #include <linux/zalloc.h>
>
> @@ -636,6 +640,21 @@ static char *build_id_cache__find_debug(const char *sbuild_id,
> if (realname && access(realname, R_OK))
> zfree(&realname);
> nsinfo__mountns_exit(&nsc);
> +
> +#if HAVE_DEBUGINFOD_SUPPORT
s/if/ifdef
> + if (realname == NULL) {
> + debuginfod_client* c = debuginfod_begin();
> + if (c != NULL) {
> + int fd = debuginfod_find_debuginfo(c,
> + (const unsigned char*)sbuild_id, 0,
> + &realname);
> + if (fd >= 0)
> + close(fd); /* retaining reference by realname */
> + debuginfod_end(c);
> + }
> + }
> +#endif
> +
> out:
> free(debugfile);
> return realname;
|