Messages in this thread Patch in this message | | | Date | Tue, 10 Jan 2017 10:18:35 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH perf/core 1/4] perf-probe: Fix to show correct locations for events on modules |
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Em Sat, Jan 07, 2017 at 02:25:09PM +0900, Masami Hiramatsu escreveu: > Fix to show correct locations for events on modules by > relocating given address. Currently the relocation is > done when we failed to find the address in debuginfo, > but for modules it always makes a mistakes.
Try to provide precise instructions on how to reproduce, for instance, here I'm not being able to reproduce:
[root@jouet ~]# perf probe -m i915 chv_prepare_pll Added new event: probe:chv_prepare_pll (on chv_prepare_pll in i915)
You can now use it in all perf tools, such as:
perf record -e probe:chv_prepare_pll -aR sleep 1
[root@jouet ~]# perf probe -l probe:chv_prepare_pll (on chv_prepare_pll in i915) probe:e1000_xmit_frame (on e1000_get_link_up_info_80003es2lan:7@intel/e1000e/80003es2lan.c in e1000e) [root@jouet ~]#
So it doesn't seem to "always make mistakes", what are the precise conditions to reproduce this problem?
Running with 'perf probe -vv -m i915 chv_prepare_pll' to get more debugging info:
Failed to get build-id from i915. Cache open error: -1 Open Debuginfo file: /lib/modules/4.9.0+/kernel/drivers/gpu/drm/i915/i915.ko Try to find probe point from debuginfo. Matched function: chv_prepare_pll [6ce853] found inline addr: 0x883a0 Probe point found: chv_prepare_pll+0 Found 1 probe_trace_events. Opening /sys/kernel/debug/tracing//kprobe_events write=1 Writing event: p:probe/chv_prepare_pll i915:chv_prepare_pll+0 Added new event: probe:chv_prepare_pll (on chv_prepare_pll in i915)
You can now use it in all perf tools, such as:
perf record -e probe:chv_prepare_pll -aR sleep 1
[root@jouet ~]#
- Arnaldo > E.g. without this fix, events on module seems wrong, > but other cases (kernel and user space) looks good. > > # perf probe -l > probe:SyS_remap_file_pages (on SyS_remap_file_pages@mm/mmap.c) > probe:chv_prepare_pll (on intel_plane_atomic_get_property+16@drm/i915/intel_atomic_plane.c in i915) > probe_perf:alias_lookup (on alias_lookup@util/alias.c in /home/mhiramat/ksrc/linux/tools/perf/perf) > > With this fix, all cases are OK now. > > # perf probe -l > probe:SyS_remap_file_pages (on SyS_remap_file_pages@mm/mmap.c) > probe:chv_prepare_pll (on chv_prepare_pll@gpu/drm/i915/intel_display.c in i915) > probe_perf:alias_lookup (on alias_lookup@util/alias.c in /home/mhiramat/ksrc/linux/tools/perf/perf) > > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> > --- > tools/perf/util/probe-finder.c | 10 +++------- > 1 file changed, 3 insertions(+), 7 deletions(-) > > diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c > index df4debe..0278fe1 100644 > --- a/tools/perf/util/probe-finder.c > +++ b/tools/perf/util/probe-finder.c > @@ -1543,16 +1543,12 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr, > Dwarf_Addr _addr = 0, baseaddr = 0; > const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp; > int baseline = 0, lineno = 0, ret = 0; > - bool reloc = false; > > -retry: > + /* We always need to relocate the address for aranges */ > + if (debuginfo__get_text_offset(dbg, &baseaddr) == 0) > + addr += baseaddr; > /* Find cu die */ > if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) { > - if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) { > - addr += baseaddr; > - reloc = true; > - goto retry; > - } > pr_warning("Failed to find debug information for address %lx\n", > addr); > ret = -EINVAL;
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