kernel/tools/perf/util/unwind-libunwind.c, branch linux-4.3.y

perf unwind: Fix a compile error

2015-06-16T13:40:03Z

When libunwind is on, there is a compile error as : util/unwind-libunwind.c:363:21: error: 'dso' undeclared (first use in this function) dso__data_put_fd(dso); This patch fixes it. Signed-off-by: Hou Pengyang Cc: Namhyung Kim Cc: Wang Nan Fixes: 4bb11d012ab248d0 ("perf tools: Add dso__data_get/put_fd()") Link: http://lkml.kernel.org/r/1434453395-10560-1-git-send-email-houpengyang@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add dso__data_get/put_fd()

2015-05-27T15:21:44Z

Using dso__data_fd() in multi-thread environment is not safe since returned fd can be closed and/or reused anytime. So convert it to the dso__data_get/put_fd() pair to protect the access with lock. The original dso__data_fd() is deprecated and kept only for testing. Signed-off-by: Namhyung Kim Acked-by: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1432137821-10853-3-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Separate eh/debug frame offset cache.

2015-03-19T16:53:27Z

Commit f1f13af99a90 ("perf callchain: Cache eh/debug frame offset for dwarf unwind") introduces a cache for .debug_frame and .eh_frame_hdr. Unfortunately, it makes them share a same cache (dso->frame_offset). Which causes unwind failure on ARM: $ perf test unwind Test dwarf unwind: FAILED! The reason is that, if a dso has '.debug_frame' but doesn't have '.eh_frame_hdr' (like ARM), dso->frame_offset will be filled by offset of '.debug_frame' during the first time calling of find_proc_info() -> read_unwind_spec_debug_frame(), and be regarded to '.eh_frame_hdr' when the second time calling of find_proc_info() -> read_unwind_spec_eh_frame(), since '.eh_frame_hdr' is checked prior to '.debug_frame'. This patch solves the problem by creating two cache fields for '.eh_frame_hdr' and '.debug_frame'. Signed-off-by: Wang Nan Acked-by: Jiri Olsa Acked-by: Namhyung Kim Cc: Li Zefan Link: http://lkml.kernel.org/r/55028BA0.1030701@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Cache eh/debug frame offset for dwarf unwind

2015-01-29T19:20:42Z

When libunwind tries to resolve callchains it needs to know the offset of .eh_frame_hdr or .debug_frame to access the dso. Since it will always return the same result for a given DSO, just cache the result as an optimization. Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Andi Kleen Cc: David Ahern Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/r/1422518843-25818-41-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf test: Fix dwarf unwind using libunwind.

2015-01-16T20:49:29Z

Perf tool fails to unwind user stack if the event raises in a shared object. This patch improves tests/dwarf-unwind.c to demonstrate the problem by utilizing commonly used glibc function "bsearch". If perf is not statically linked, the testcase will try to unwind a mixed call trace. By debugging libunwind I found that there is a bug in unwind-libunwind: it always passes 0 as segbase to libunwind, cause libunwind unable to locate debug_frame entry fir first level ip address (I add some more debugging output into libunwind to make things clear): >_Uarm_dwarf_find_debug_frame: start_ip = 10be98, end_ip = 10c2a4 >_Uarm_dwarf_find_debug_frame: found debug_frame table `/lib/libc-2.18.so': segbase=0x0, len=7, gp=0x0, table_data=0x449388 >_Uarm_dwarf_search_unwind_table: call lookup:ip = b6cd3bcc, segbase = 0, rel_ip = b6cd3bcc >lookup: e->start_ip_offset = bcf18 (rel_ip = b6cd3bcc) >lookup: e->start_ip_offset = 6d314 (rel_ip = b6cd3bcc) >lookup: e->start_ip_offset = 33d0c (rel_ip = b6cd3bcc) ... >lookup: e->start_ip_offset = 15d0c (rel_ip = b6cd3bcc) >lookup: e->start_ip_offset = 15c40 (rel_ip = b6cd3bcc) >_Uarm_dwarf_search_unwind_table: IP b6cd3bcc inside range b6c12000-b6d4c000, but no explicit unwind info found >put_rs_cache: unmasking signals/interrupts and releasing lock >_Uarm_dwarf_step: returning -10 >_Uarm_step: dwarf_step()=-10 This patch passes map->start as segbase to dwarf_find_debug_frame(), so di will be initialized correctly. In addition, dso and executable are different when setting segbase. This patch first check whether the elf is executable, and pass segbase only for shared object. Signed-off-by: Wang Nan Acked-by: Jiri Olsa Cc: Ingo Molnar Cc: Jiri Olsa Cc: Li Zefan Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1421203007-75799-1-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf callchains: Use thread->mg->machine

2014-10-29T12:32:46Z

The unwind__get_entries() already receives the thread parameter, from where it can obtain the matching machine structure, shorten the signature. Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Don Zickus Cc: Frederic Weisbecker Cc: Jean Pihet Cc: Jiri Olsa Cc: Mike Galbraith Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-isjc6bm8mv4612mhi6af64go@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: A thread's machine can be found via thread->mg->machine

2014-10-29T12:32:46Z

So stop passing both machine and thread to several thread methods, reducing function signature length. Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Don Zickus Cc: Frederic Weisbecker Cc: Jean Pihet Cc: Jiri Olsa Cc: Mike Galbraith Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-ckcy19dcp1jfkmdihdjcqdn1@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Use global caching provided by libunwind

2014-10-29T12:25:22Z

The libunwind provides two caching policy which are global and per-thread. As perf unwinds callchains in a single thread, it'd sufficient to use global caching. This speeds up my perf report from 14s to 7s on a ~260MB data file. Although the output sometimes contains a slight difference (~0.01% in terms of number of lines printed) on callchains which were not resolved. Signed-off-by: Namhyung Kim Acked-by: Jean Pihet Cc: Arun Sharma Cc: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jean Pihet Cc: Jiri Olsa Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1412556363-26229-4-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Create an address space per thread

2014-10-15T20:38:23Z

The unw_addr_space_t in libunwind represents an address space to be used for stack unwinding. It doesn't need to be create/destory everytime to unwind callchain (as in get_entries) and can have a same lifetime as thread (unless exec called). So move the address space construction/destruction logic to the thread lifetime handling functions. This is a preparation to enable caching in the unwind library. Note that it saves unw_addr_space_t object using thread__set_priv(). It seems currently only used by perf trace and perf kvm stat commands which don't use callchain. Signed-off-by: Namhyung Kim Acked-by: Jean Pihet Acked-by: Jiri Olsa Cc: Arun Sharma Cc: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jean Pihet Cc: Jiri Olsa Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1412556363-26229-3-git-send-email-namhyung@kernel.org [ Fixup unwind-libunwind.c missing CALLCHAIN_DWARF definition, added missing __maybe_unused on unused parameters in stubs at util/unwind.h ] Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Move pr_* debug macros into debug object

2014-07-17T15:58:39Z

Moving pr_* debug macros to have it with in same object as debug variables, becase we will change them to use verbose variable in next patch. Signed-off-by: Jiri Olsa Cc: Corey Ashford Cc: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1405374411-29012-3-git-send-email-jolsa@kernel.org [ Add missing debug.h include in python scripting glue and in the libdw unwind lib ] Signed-off-by: Arnaldo Carvalho de Melo