kernel/linux.git/tools/perf/util/session.c, branch v4.4.22

perf kvm record/report: 'unprocessable sample' error while recording/reporting guest data

2016-02-25T20:01:20+00:00

commit 3caeaa562733c4836e61086ec07666635006a787 upstream. While recording guest samples in host using perf kvm record, it will populate unprocessable sample error, though samples will be recorded properly. While generating report using perf kvm report, no samples will be processed and same error will populate. We have seen this behaviour with upstream perf(4.4-rc3) on x86 and ppc64 hardware. Reason behind this failure is, when it tries to fetch machine from rb_tree of machines, it fails. As a part of tracing a bug, we figured out that this code was incorrectly refactored in commit 54245fdc3576 ("perf session: Remove wrappers to machines__find"). This patch will change the functionality such that if it can't fetch machine in first trial, it will create one node of machine and add that to rb_tree. So next time when it tries to fetch same machine from rb_tree, it won't fail. Actually it was the case before refactoring of code in aforementioned commit. This patch is generated from acme perf/core branch. Below I've mention an example that demonstrate the behaviour before and after applying patch. Before applying patch: [Note: One needs to run guest before recording data in host] ravi@ravi-bangoria:~$ ./perf kvm record -a Warning: 5903 unprocessable samples recorded. Do you have a KVM guest running and not using 'perf kvm'? [ perf record: Captured and wrote 1.409 MB perf.data.guest (285 samples) ] ravi@ravi-bangoria:~$ ./perf kvm report --stdio Warning: 5903 unprocessable samples recorded. Do you have a KVM guest running and not using 'perf kvm'? # To display the perf.data header info, please use --header/--header-only options. # # Total Lost Samples: 0 # # Samples: 285 of event 'cycles' # Event count (approx.): 88715406 # # Overhead Command Shared Object Symbol # ........ ....... ............. ...... # # (For a higher level overview, try: perf report --sort comm,dso) # After applying patch: ravi@ravi-bangoria:~$ ./perf kvm record -a [ perf record: Captured and wrote 1.188 MB perf.data.guest (17 samples) ] ravi@ravi-bangoria:~$ ./perf kvm report --stdio # To display the perf.data header info, please use --header/--header-only options. # # Total Lost Samples: 0 # # Samples: 17 of event 'cycles' # Event count (approx.): 700746 # # Overhead Command Shared Object Symbol # ........ ....... ................ ...................... # 34.19% :5758 [unknown] [g] 0xffffffff818682ab 22.79% :5758 [unknown] [g] 0xffffffff812dc7f8 22.79% :5758 [unknown] [g] 0xffffffff818650d0 14.83% :5758 [unknown] [g] 0xffffffff8161a1b6 2.49% :5758 [unknown] [g] 0xffffffff818692bf 0.48% :5758 [unknown] [g] 0xffffffff81869253 0.05% :5758 [unknown] [g] 0xffffffff81869250 Signed-off-by: Ravi Bangoria Cc: Naveen N. Rao Fixes: 54245fdc3576 ("perf session: Remove wrappers to machines__find") Link: http://lkml.kernel.org/r/1449471302-11283-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Greg Kroah-Hartman

perf session: Add missing newlines to some pr_err() calls

2015-11-11T21:41:31+00:00

Before: [acme@zoo linux]$ perf evlist WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? non matching sample_type[acme@zoo linux]$ After: [acme@zoo linux]$ perf evlist WARNING: The perf.data file's data size field is 0 which is unexpected. Was the 'perf record' command properly terminated? non matching sample_type [acme@zoo linux]$ Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-wscok3a2s7yrj8156oc2r6qe@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf top: Register idle thread

2015-10-01T12:54:33+00:00

The perf top didn't add the idle/swapper thread to the machine's thread list and its comm was displayed as ':0'. Fix it. Signed-off-by: Namhyung Kim Cc: David Ahern Cc: Jiri Olsa Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1443577526-3240-3-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf script: Add a setting for maximum stack depth

2015-09-28T20:08:48+00:00

Add a setting for maximum stack depth in preparation for allowing for synthesized callchains. Signed-off-by: Adrian Hunter Cc: Jiri Olsa Link: http://lkml.kernel.org/r/1443186956-18718-19-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf session: Warn when AUX data has been lost

2015-09-28T19:51:33+00:00

By default 'perf record' will postprocess the perf.data file to determine build-ids. When that happens, the number of lost perf events is displayed. Make that also happen for AUX events. Signed-off-by: Adrian Hunter Cc: Jiri Olsa Link: http://lkml.kernel.org/r/1443186956-18718-7-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

Merge branch 'perf/urgent' into perf/core to pick up fixes before pulling new changes

2015-09-23T07:42:11+00:00

Signed-off-by: Ingo Molnar

perf record: Avoid infinite loop at buildid processing with no samples

2015-09-18T15:31:40+00:00

If a session contains no events, we can get stuck in an infinite loop in __perf_session__process_events, with a non-zero file_size and data_offset, but a zero data_size. In this case, we can mmap the entirety of the file (consisting of the file and attribute headers), and fetch_mmaped_event will correctly refuse to read any (unmapped and non-existent) event headers. This causes __perf_session__process_events to unmap the file and retry with the exact same parameters, getting stuck in an infinite loop. This has been observed to result in an exit-time hang when counting rare/unschedulable events with perf record, and can be triggered artificially with the script below: ---- #!/bin/sh printf "REPRO: launching perf\n"; ./perf record -e software/config=9/ sleep 1 & PERF_PID=$!; sleep 0.002; kill -2 $PERF_PID; printf "REPRO: waiting for perf (%d) to exit...\n" "$PERF_PID"; wait $PERF_PID; printf "REPRO: perf exited\n"; ---- To avoid this, have __perf_session__process_events bail out early when the file has no data (i.e. it has no events). Commiter note: I only managed to reproduce this when setting /proc/sys/kernel/kptr_restrict to '1' and changing the code to purposefully not process any samples and no synthesized samples, i.e. kptr_restrict prevents 'record' from synthesizing the kernel mmaps for vmlinux + modules and since it is a workload started from perf, we don't synthesize mmap/comm records for existing threads. Adrian Hunter managed to reproduce it in his environment tho. Signed-off-by: Mark Rutland Tested-by: Arnaldo Carvalho de Melo Tested-by: Adrian Hunter Cc: Jiri Olsa Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1442423929-12253-1-git-send-email-mark.rutland@arm.com Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Add pointer to sample's environment

2015-09-14T15:50:29+00:00

The 'struct machine' represents the machine where the samples were/are being collected, and we also have a 'struct perf_env' with extra details about such machine, that we were collecting at 'perf.data' creation time but we also needed when no perf.data file is being used, such as in 'perf top'. So, get those structs closer together, as they provide a bigger picture of the sample's environment. In 'perf session', when the file argument is NULL, we can assume that the tool is sampling the running machine, so point machine->env to the global put in place in previous patches, while set it to the perf_header.env one when reading from a file. This paves the way for machine->env to be used in perf_event__preprocess_sample to populate addr_location.socket. Tested-by: Wang Nan Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Kan Liang Cc: Namhyung Kim Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-2ajotl0khscutm68exictoy9@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf env: Move perf_env out of header.h and session.c into separate object

2015-09-14T15:50:19+00:00

Since it can be used separately from 'perf_session' and 'perf_header', move it to separate include file and object, next csets will try to move a perf_env__init() routine. Tested-by: Wang Nan Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Kan Liang Cc: Namhyung Kim Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-ff2rw99tsn670y1b6gxbwdsi@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf session: Don't call dump_sample() when evsel is NULL

2015-09-04T15:01:04+00:00

Need to check evsel before passing it to dump_sample(). Signed-off-by: Kan Liang Cc: Adrian Hunter Cc: Andi Kleen Cc: Andy Lutomirski Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/r/1441283463-51050-5-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo