linux/tools/perf, branch v4.6

perf stat: Fallback to user only counters when perf_event_paranoid > 1

2016-05-12T19:25:18Z

After 0161028b7c8a ("perf/core: Change the default paranoia level to 2") 'perf stat' fails for users without CAP_SYS_ADMIN, so just use 'perf_evsel__fallback()' to have the same behaviour as 'perf record', i.e. set perf_event_attr.exclude_kernel to 1. Now: [acme@jouet linux]$ perf stat usleep 1 Performance counter stats for 'usleep 1': 0.352536 task-clock:u (msec) # 0.423 CPUs utilized 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 49 page-faults:u # 0.139 M/sec 309,407 cycles:u # 0.878 GHz 243,791 instructions:u # 0.79 insn per cycle 49,622 branches:u # 140.757 M/sec 3,884 branch-misses:u # 7.83% of all branches 0.000834174 seconds time elapsed [acme@jouet linux]$ Reported-by: Ingo Molnar Cc: Adrian Hunter Cc: Andy Lutomirski Cc: David Ahern Cc: Jiri Olsa Cc: Kees Cook Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-b20jmx4dxt5hpaa9t2rroi0o@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf evsel: Handle EACCESS + perf_event_paranoid=2 in fallback()

2016-05-12T19:13:16Z

Now with the default for the kernel.perf_event_paranoid sysctl being 2 [1] we need to fall back to :u, i.e. to set perf_event_attr.exclude_kernel to 1. Before: [acme@jouet linux]$ perf record usleep 1 Error: You may not have permission to collect stats. Consider tweaking /proc/sys/kernel/perf_event_paranoid, which controls use of the performance events system by unprivileged users (without CAP_SYS_ADMIN). The current value is 2: -1: Allow use of (almost) all events by all users >= 0: Disallow raw tracepoint access by users without CAP_IOC_LOCK >= 1: Disallow CPU event access by users without CAP_SYS_ADMIN >= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN [acme@jouet linux]$ After: [acme@jouet linux]$ perf record usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.016 MB perf.data (7 samples) ] [acme@jouet linux]$ perf evlist cycles:u [acme@jouet linux]$ perf evlist -v cycles:u: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, exclude_kernel: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 [acme@jouet linux]$ And if the user turns on verbose mode, an explanation will appear: [acme@jouet linux]$ perf record -v usleep 1 Warning: kernel.perf_event_paranoid=2, trying to fall back to excluding kernel samples mmap size 528384B [ perf record: Woken up 1 times to write data ] Looking at the vmlinux_path (8 entries long) Using /lib/modules/4.6.0-rc7+/build/vmlinux for symbols [ perf record: Captured and wrote 0.016 MB perf.data (7 samples) ] [acme@jouet linux]$ [1] 0161028b7c8a ("perf/core: Change the default paranoia level to 2") Reported-by: Ingo Molnar Cc: Adrian Hunter Cc: Andy Lutomirski Cc: David Ahern Cc: Jiri Olsa Cc: Kees Cook Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-b20jmx4dxt5hpaa9t2rroi0o@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf evsel: Improve EPERM error handling in open_strerror()

2016-05-12T18:44:55Z

We were showing a hardcoded default value for the kernel.perf_event_paranoid sysctl, now that it became more paranoid (1 -> 2 [1]), this would need to be updated, instead show the current value: [acme@jouet linux]$ perf record ls Error: You may not have permission to collect stats. Consider tweaking /proc/sys/kernel/perf_event_paranoid, which controls use of the performance events system by unprivileged users (without CAP_SYS_ADMIN). The current value is 2: -1: Allow use of (almost) all events by all users >= 0: Disallow raw tracepoint access by users without CAP_IOC_LOCK >= 1: Disallow CPU event access by users without CAP_SYS_ADMIN >= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN [acme@jouet linux]$ [1] 0161028b7c8a ("perf/core: Change the default paranoia level to 2") Reported-by: Ingo Molnar Cc: Adrian Hunter Cc: Andy Lutomirski Cc: David Ahern Cc: Jiri Olsa Cc: Kees Cook Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-0gc4rdpg8d025r5not8s8028@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Check if dwarf_getlocations() is available

2016-05-12T14:26:59Z

If not, tell the user that: config/Makefile:273: Old libdw.h, finding variables at given 'perf probe' point will not work, install elfutils-devel/libdw-dev >= 0.157 And return -ENOTSUPP in die_get_var_range(), failing features that need it, like the one pointed out above. This fixes the build on older systems, such as Ubuntu 12.04.5. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Vinson Lee Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-9l7luqkq4gfnx7vrklkq4obs@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf dwarf: Guard !x86_64 definitions under #ifdef else clause

2016-05-12T14:26:59Z

To fix the build on Fedora Rawhide (gcc 6.0.0 20160311 (Red Hat 6.0.0-0.17): CC /tmp/build/perf/arch/x86/util/dwarf-regs.o arch/x86/util/dwarf-regs.c:66:36: error: 'x86_32_regoffset_table' defined but not used [-Werror=unused-const-variable=] static const struct pt_regs_offset x86_32_regoffset_table[] = { ^~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-fghuksc1u8ln82bof4lwcj0o@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Use readdir() instead of deprecated readdir_r()

2016-05-12T14:26:58Z

The readdir() function is thread safe as long as just one thread uses a DIR, which is the case when parsing tracepoint event definitions, to avoid breaking the build with glibc-2.23.90 (upcoming 2.24), use it instead of readdir_r(). See: http://man7.org/linux/man-pages/man3/readdir.3.html "However, in modern implementations (including the glibc implementation), concurrent calls to readdir() that specify different directory streams are thread-safe. In cases where multiple threads must read from the same directory stream, using readdir() with external synchronization is still preferable to the use of the deprecated readdir_r(3) function." Noticed while building on a Fedora Rawhide docker container. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-wddn49r6bz6wq4ee3dxbl7lo@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf thread_map: Use readdir() instead of deprecated readdir_r()

2016-05-12T14:26:58Z

The readdir() function is thread safe as long as just one thread uses a DIR, which is the case in thread_map, so, to avoid breaking the build with glibc-2.23.90 (upcoming 2.24), use it instead of readdir_r(). See: http://man7.org/linux/man-pages/man3/readdir.3.html "However, in modern implementations (including the glibc implementation), concurrent calls to readdir() that specify different directory streams are thread-safe. In cases where multiple threads must read from the same directory stream, using readdir() with external synchronization is still preferable to the use of the deprecated readdir_r(3) function." Noticed while building on a Fedora Rawhide docker container. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-del8h2a0f40z75j4r42l96l0@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf script: Use readdir() instead of deprecated readdir_r()

2016-05-12T14:26:57Z

The readdir() function is thread safe as long as just one thread uses a DIR, which is the case in 'perf script', so, to avoid breaking the build with glibc-2.23.90 (upcoming 2.24), use it instead of readdir_r(). See: http://man7.org/linux/man-pages/man3/readdir.3.html "However, in modern implementations (including the glibc implementation), concurrent calls to readdir() that specify different directory streams are thread-safe. In cases where multiple threads must read from the same directory stream, using readdir() with external synchronization is still preferable to the use of the deprecated readdir_r(3) function." Noticed while building on a Fedora Rawhide docker container. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-mt3xz7n2hl49ni2vx7kuq74g@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Use readdir() instead of deprecated readdir_r()

2016-05-12T13:22:54Z

The readdir() function is thread safe as long as just one thread uses a DIR, which is the case when synthesizing events for pre-existing threads by traversing /proc, so, to avoid breaking the build with glibc-2.23.90 (upcoming 2.24), use it instead of readdir_r(). See: http://man7.org/linux/man-pages/man3/readdir.3.html "However, in modern implementations (including the glibc implementation), concurrent calls to readdir() that specify different directory streams are thread-safe. In cases where multiple threads must read from the same directory stream, using readdir() with external synchronization is still preferable to the use of the deprecated readdir_r(3) function." Noticed while building on a Fedora Rawhide docker container. CC /tmp/build/perf/util/event.o util/event.c: In function '__event__synthesize_thread': util/event.c:466:2: error: 'readdir_r' is deprecated [-Werror=deprecated-declarations] while (!readdir_r(tasks, &dirent, &next) && next) { ^~~~~ In file included from /usr/include/features.h:368:0, from /usr/include/stdint.h:25, from /usr/lib/gcc/x86_64-redhat-linux/6.0.0/include/stdint.h:9, from /git/linux/tools/include/linux/types.h:6, from util/event.c:1: /usr/include/dirent.h:189:12: note: declared here Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-i1vj7nyjp2p750rirxgrfd3c@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf diff: Fix duplicated output column

2016-05-11T14:55:32Z

The commit b97511c5bc94 ("perf tools: Add overhead/overhead_children keys defaults via string") moved initialization of column headers but it missed to check the sort__mode. As 'perf diff' doesn't call perf_hpp__init(), the setup_overhead() also should not be called. Before: # Baseline Delta Children Overhead Shared Object Symbol # ........ ....... ........ ........ ................... ....................... # 28.48% -28.47% 28.48% 28.48% [kernel.vmlinux ] [k] intel_idle 11.51% -11.47% 11.51% 11.51% libxul.so [.] 0x0000000001a360f7 3.49% -3.49% 3.49% 3.49% [kernel.vmlinux] [k] generic_exec_single 2.91% -2.89% 2.91% 2.91% libdbus-1.so.3.8.11 [.] 0x000000000000cdc2 2.86% -2.85% 2.86% 2.86% libxcb.so.1.1.0 [.] 0x000000000000c890 2.44% -2.39% 2.44% 2.44% [kernel.vmlinux] [k] perf_event_aux_ctx After: # Baseline Delta Shared Object Symbol # ........ ....... ................... ....................... # 28.48% -28.47% [kernel.vmlinux] [k] intel_idle 11.51% -11.47% libxul.so [.] 0x0000000001a360f7 3.49% -3.49% [kernel.vmlinux] [k] generic_exec_single 2.91% -2.89% libdbus-1.so.3.8.11 [.] 0x000000000000cdc2 2.86% -2.85% libxcb.so.1.1.0 [.] 0x000000000000c890 2.44% -2.39% [kernel.vmlinux] [k] perf_event_aux_ctx Signed-off-by: Namhyung Kim Signed-off-by: Arnaldo Carvalho de Melo Acked-by: Jiri Olsa Cc: # 4.5+ Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: b97511c5bc94 ("perf tools: Add overhead/overhead_children keys defaults via string") Link: http://lkml.kernel.org/r/1462890384-12486-2-git-send-email-acme@kernel.org Signed-off-by: Ingo Molnar