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perf
perf-machine-refine-the-function-for-lbr-call-s...
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File perf-machine-refine-the-function-for-lbr-call-stack-reconstruction.patch of Package perf
From: Kan Liang <kan.liang@linux.intel.com> Date: Thu, 19 Mar 2020 13:25:06 -0700 Subject: perf machine: Refine the function for LBR call stack reconstruction Git-commit: e48b8311ca4538ec716196a1625812b045999f21 Patch-mainline: v5.8-rc1 References: jsc#SLE-12718 LBR only collect the user call stack. To reconstruct a call stack, both kernel call stack and user call stack are required. The function resolve_lbr_callchain_sample() mix the kernel call stack and user call stack. Now, with the help of HW idx, perf tool can reconstruct a more complete call stack by adding some user call stack from previous sample. However, current implementation is hard to be extended to support it. Current code path for resolve_lbr_callchain_sample() for (j = 0; j < mix_chain_nr; j++) { if (ORDER_CALLEE) { if (kernel callchain) Fill callchain info else if (LBR callchain) Fill callchain info } else { if (LBR callchain) Fill callchain info else if (kernel callchain) Fill callchain info } add_callchain_ip(); } With the patch, if (ORDER_CALLEE) { for (j = 0; j < NUM of kernel callchain) { Fill callchain info add_callchain_ip(); } for (; j < mix_chain_nr) { Fill callchain info add_callchain_ip(); } } else { for (; j < NUM of LBR callchain) { Fill callchain info add_callchain_ip(); } for (j = 0; j < mix_chain_nr) { Fill callchain info add_callchain_ip(); } } No functional changes. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Acked-by: Jiri Olsa <jolsa@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Pavel Gerasimov <pavel.gerasimov@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Cc: Stephane Eranian <eranian@google.com> Cc: Vitaly Slobodskoy <vitaly.slobodskoy@intel.com> Link: http://lore.kernel.org/lkml/20200319202517.23423-7-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Tony Jones <tonyj@suse.de> --- tools/perf/util/machine.c | 111 +++++++++++++++++++++++++++++++--------------- 1 file changed, 76 insertions(+), 35 deletions(-) diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index be1bd9277471..0da540e6f803 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -2214,6 +2214,7 @@ static int resolve_lbr_callchain_sample(struct thread *thread, bool branch; struct branch_flags *flags; int mix_chain_nr; + int err; for (i = 0; i < chain_nr; i++) { if (chain->ips[i] == PERF_CONTEXT_USER) @@ -2239,50 +2240,90 @@ static int resolve_lbr_callchain_sample(struct thread *thread, */ mix_chain_nr = i + 1 + lbr_nr + 1; - for (j = 0; j < mix_chain_nr; j++) { - int err; - - branch = false; - flags = NULL; - - if (callchain_param.order == ORDER_CALLEE) { - if (j < i + 1) - ip = chain->ips[j]; - else if (j > i + 1) { - k = j - i - 2; - ip = entries[k].from; - branch = true; - flags = &entries[k].flags; - } else { - ip = entries[0].to; - branch = true; - flags = &entries[0].flags; - branch_from = entries[0].from; - } - } else { - if (j < lbr_nr) { - k = lbr_nr - j - 1; - ip = entries[k].from; - branch = true; - flags = &entries[k].flags; - } else if (j > lbr_nr) - ip = chain->ips[i + 1 - (j - lbr_nr)]; - else { - ip = entries[0].to; - branch = true; - flags = &entries[0].flags; - branch_from = entries[0].from; - } + if (callchain_param.order == ORDER_CALLEE) { + /* Add kernel ip */ + for (j = 0; j < i + 1; j++) { + ip = chain->ips[j]; + branch = false; + flags = NULL; + err = add_callchain_ip(thread, cursor, parent, + root_al, &cpumode, ip, + branch, flags, NULL, + branch_from); + if (err) + goto error; } + /* Add LBR ip from first entries.to */ + ip = entries[0].to; + branch = true; + flags = &entries[0].flags; + branch_from = entries[0].from; + err = add_callchain_ip(thread, cursor, parent, + root_al, &cpumode, ip, + branch, flags, NULL, + branch_from); + if (err) + goto error; + /* Add LBR ip from entries.from one by one. */ + for (j = i + 2; j < mix_chain_nr; j++) { + k = j - i - 2; + ip = entries[k].from; + branch = true; + flags = &entries[k].flags; + + err = add_callchain_ip(thread, cursor, parent, + root_al, &cpumode, ip, + branch, flags, NULL, + branch_from); + if (err) + goto error; + } + } else { + /* Add LBR ip from entries.from one by one. */ + for (j = 0; j < lbr_nr; j++) { + k = lbr_nr - j - 1; + ip = entries[k].from; + branch = true; + flags = &entries[k].flags; + + err = add_callchain_ip(thread, cursor, parent, + root_al, &cpumode, ip, + branch, flags, NULL, + branch_from); + if (err) + goto error; + } + + /* Add LBR ip from first entries.to */ + ip = entries[0].to; + branch = true; + flags = &entries[0].flags; + branch_from = entries[0].from; err = add_callchain_ip(thread, cursor, parent, root_al, &cpumode, ip, branch, flags, NULL, branch_from); if (err) - return (err < 0) ? err : 0; + goto error; + + /* Add kernel ip */ + for (j = lbr_nr + 1; j < mix_chain_nr; j++) { + ip = chain->ips[i + 1 - (j - lbr_nr)]; + branch = false; + flags = NULL; + err = add_callchain_ip(thread, cursor, parent, + root_al, &cpumode, ip, + branch, flags, NULL, + branch_from); + if (err) + goto error; + } } return 1; + +error: + return (err < 0) ? err : 0; } static int find_prev_cpumode(struct ip_callchain *chain, struct thread *thread,
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