Messages in this thread | | | Date | Tue, 10 Jan 2017 23:15:35 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH perf/core 1/4] perf-probe: Fix to show correct locations for events on modules |
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On Tue, 10 Jan 2017 10:18:35 -0300 Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
> 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?
Hmm, OK, I also found same issue. I'll recheck that...
Thank you,
> > 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;
-- Masami Hiramatsu <mhiramat@kernel.org>
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