kernel.git/tools/perf/util/symbol.c, branch linux-3.16.y

perf symbols: Fix symbols__fixup_end heuristic for corner cases

2017-07-18T17:40:19Z

commit e7ede72a6d40cb3a30c087142d79381ca8a31dab upstream. The current symbols__fixup_end() heuristic for the last entry in the rb tree is suboptimal as it leads to not being able to recognize the symbol in the call graph in a couple of corner cases, for example: i) If the symbol has a start address (f.e. exposed via kallsyms) that is at a page boundary, then the roundup(curr->start, 4096) for the last entry will result in curr->start == curr->end with a symbol length of zero. ii) If the symbol has a start address that is shortly before a page boundary, then also here, curr->end - curr->start will just be very few bytes, where it's unrealistic that we could perform a match against. Instead, change the heuristic to roundup(curr->start, 4096) + 4096, so that we can catch such corner cases and have a better chance to find that specific symbol. It's still just best effort as the real end of the symbol is unknown to us (and could even be at a larger offset than the current range), but better than the current situation. Alexei reported that he recently run into case i) with a JITed eBPF program (these are all page aligned) as the last symbol which wasn't properly shown in the call graph (while other eBPF program symbols in the rb tree were displayed correctly). Since this is a generic issue, lets try to improve the heuristic a bit. Reported-and-Tested-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Fixes: 2e538c4a1847 ("perf tools: Improve kernel/modules symbol lookup") Link: http://lkml.kernel.org/r/bb5c80d27743be6f12afc68405f1956a330e1bc9.1489614365.git.daniel@iogearbox.net Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Ben Hutchings

perf symbols: Fixup symbol sizes before picking best ones

2017-02-23T03:53:56Z

commit 432746f8e0b6a82ba832b771afe31abd51af6752 upstream. When we call symbol__fixup_duplicate() we use algorithms to pick the "best" symbols for cases where there are various functions/aliases to an address, and those check zero size symbols, which, before calling symbol__fixup_end() are _all_ symbols in a just parsed kallsyms file. So first fixup the end, then fixup the duplicates. Found while trying to figure out why 'perf test vmlinux' failed, see the output of 'perf test -v vmlinux' to see cases where the symbols picked as best for vmlinux don't match the ones picked for kallsyms. Cc: Anton Blanchard Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Wang Nan Fixes: 694bf407b061 ("perf symbols: Add some heuristics for choosing the best duplicate symbol") Link: http://lkml.kernel.org/n/tip-rxqvdgr0mqjdxee0kf8i2ufn@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Ben Hutchings

perf symbols: Store if there is a filter in place

2015-08-11T08:57:25Z

commit 0bc2f2f7d080561cc484d2d0a162a9396bed3383 upstream. When setting yup the symbols library we setup several filter lists, for dsos, comms, symbols, etc, and there is code that, if there are filters, do certain operations, like recalculate the number of non filtered histogram entries in the top/report TUI. But they were considering just the "Zoom" filters, when they need to take into account as well the above mentioned filters (perf top --comms, --dsos, etc). So store in symbol_conf.has_filter true if any of those filters is in place. Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Namhyung Kim Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-f5edfmhq69vfvs1kmikq1wep@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo [ luis: backported to 3.16: adjusted context ] Signed-off-by: Luis Henriques

perf tools: Enable --children option by default

2014-06-01T12:35:08Z

Now perf top and perf report will show children column by default if it has callchain information. Requested-by: Ingo Molnar Signed-off-by: Namhyung Kim Tested-by: Rodrigo Campos Tested-by: Arun Sharma Cc: Frederic Weisbecker Link: http://lkml.kernel.org/r/1401335910-16832-23-git-send-email-namhyung@kernel.org Signed-off-by: Jiri Olsa

Merge branch 'perf/urgent' into perf/core

2014-03-11T10:53:50Z

Merge the latest fixes. Signed-off-by: Ingo Molnar

perf symbols: Check compatible symtab type before loading dso

2014-02-24T19:25:01Z

When loading a dso it'll look for symbol tables of all possible types. However it's just wasted of time to check incompatible types - like trying kernel module when loading user library. Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Cody P Schafer Cc: Ingo Molnar Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/r/1392859976-32760-4-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Destroy unused symsrcs

2014-02-24T14:13:08Z

Stephane reported that perf report and annotate failed to process data using lots of (> 500) shared libraries. It was because of the limit on number of open files (ulimit -n). Currently when perf loads a DSO, it'll look for normal and dynamic symbol tables. And if it fails to find out both tables, it'll iterate all of possible symtab types. But many of them are useless since they have no additional information and the problem is that it's not closing those files even though they're not used. Fix it. Reported-by: Stephane Eranian Signed-off-by: Namhyung Kim Cc: Cody P Schafer Cc: Ingo Molnar Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1392859976-32760-2-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: No need to export dso__first_symbol

2014-02-18T12:34:49Z

There are no users outside the file that defines it. Cc: Adrian Hunter Cc: David Ahern Cc: Frederic Weisbecker 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-sybihqycxrmssa4df9516jib@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Adjust kallsyms for relocated kernel

2014-01-31T20:21:53Z

If the kernel is relocated at boot time, kallsyms will not match data recorded previously. That does not matter for modules because they are corrected anyway. It also does not matter if vmlinux is being used for symbols. But if perf tools has only kallsyms then the symbols will not match. Fix by applying the delta gained by comparing the old and current addresses of the relocation reference symbol. Signed-off-by: Adrian Hunter Tested-by: Jiri Olsa Cc: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jiri Olsa Cc: Mike Galbraith Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/r/1391004884-10334-9-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Prevent the use of kcore if the kernel has moved

2014-01-31T20:21:51Z

Use of kcore is predicated upon it matching the recorded data. If the kernel has been relocated at boot time (i.e. since the data was recorded) then do not use kcore. Note that it is possible to make a copy of kcore at the time the data is recorded using 'perf buildid-cache'. Then the perf tools will use the copy because it does match the data. Signed-off-by: Adrian Hunter Tested-by: Jiri Olsa Cc: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jiri Olsa Cc: Mike Galbraith Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/r/1391004884-10334-7-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo