Messages in this thread | | | Date | Wed, 11 Dec 2019 14:46:43 +0000 | From | Mark Rutland <> | Subject | Re: [PATCHES] Fix 'perf top' breakage on architectures not providing get_cpuid() Re: perf top for arm64? |
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On Wed, Dec 11, 2019 at 10:33:19AM -0300, Arnaldo Carvalho de Melo wrote: > So can you take a look at the two patches below and provide me Acked-by > and/or Reviewed-by and/or Tested-by?
I just gave this a spin. With vanilla v5.5-rc1 perf top behaves as John reported, and with these applied atop perf works as expected:
Tested-by: Mark Rutland <mark.rutland@arm.com>
From scaning the code, the only other user of get_cpuid() that ends up giving up is perf kvm, but AFAICT that never supported arm64, so that looks sound to me:
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Thanks, Mark.
> From 53c6cde6a71a1a9283763bd2e938b229b50c2cd5 Mon Sep 17 00:00:00 2001 > From: Arnaldo Carvalho de Melo <acme@redhat.com> > Date: Wed, 11 Dec 2019 10:09:24 -0300 > Subject: [PATCH 1/2] perf arch: Make the default get_cpuid() return compatible > error > > Some of the functions calling get_cpuid() propagate back the error it > returns, and all are using errno (positive) values, make the weak > default get_cpuid() function return ENOSYS to be consistent and to allow > checking if this is an arch not providing this function or if a provided > one is having trouble getting the cpuid, to decide if the warning should > be provided to the user or just a debug message should be emitted. > > Cc: Adrian Hunter <adrian.hunter@intel.com> > Cc: Jiri Olsa <jolsa@kernel.org> > Cc: John Garry <john.garry@huawei.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Namhyung Kim <namhyung@kernel.org> > Cc: Will Deacon <will@kernel.org> > Link: https://lkml.kernel.org/n/tip-lxwjr0cd2eggzx04a780ffrv@git.kernel.org > Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> > --- > tools/perf/util/header.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c > index becc2d109423..4d39a75551a0 100644 > --- a/tools/perf/util/header.c > +++ b/tools/perf/util/header.c > @@ -850,7 +850,7 @@ int __weak strcmp_cpuid_str(const char *mapcpuid, const char *cpuid) > */ > int __weak get_cpuid(char *buffer __maybe_unused, size_t sz __maybe_unused) > { > - return -1; > + return ENOSYS; /* Not implemented */ > } > > static int write_cpuid(struct feat_fd *ff, > -- > 2.21.0 > > From c6c6a3e2eb6982e37294abcac389effd298cf730 Mon Sep 17 00:00:00 2001 > From: Arnaldo Carvalho de Melo <acme@redhat.com> > Date: Wed, 11 Dec 2019 10:21:59 -0300 > Subject: [PATCH 2/2] perf top: Do not bail out when perf_env__read_cpuid() > returns ENOSYS > > 'perf top' stopped working on hw architectures that do not provide a > get_cpuid() implementation and thus fallback to the weak get_cpuid() > default function. > > This is done because at annotation time we may need it in the arch > specific annotation init routine, but that is only being used by arches > that do provide a get_cpuid() implementation: > > $ find tools/ -name "*.[ch]" | xargs grep 'evlist->env' > tools/perf/builtin-top.c: top.evlist->env = &perf_env; > tools/perf/util/evsel.c: return evsel->evlist->env; > tools/perf/util/s390-cpumsf.c: sf->machine_type = s390_cpumsf_get_type(session->evlist->env->cpuid); > tools/perf/util/header.c: session->evlist->env = &header->env; > tools/perf/util/sample-raw.c: const char *arch_pf = perf_env__arch(evlist->env); > $ > > $ find tools/perf/arch -name "*.[ch]" | xargs grep -w get_cpuid > tools/perf/arch/x86/util/auxtrace.c: ret = get_cpuid(buffer, sizeof(buffer)); > tools/perf/arch/x86/util/header.c:get_cpuid(char *buffer, size_t sz) > tools/perf/arch/powerpc/util/header.c:get_cpuid(char *buffer, size_t sz) > tools/perf/arch/s390/util/header.c: * Implementation of get_cpuid(). > tools/perf/arch/s390/util/header.c:int get_cpuid(char *buffer, size_t sz) > tools/perf/arch/s390/util/header.c: if (buf && get_cpuid(buf, 128)) > $ > > For 'report' or 'script', i.e. tools working on perf.data files, that is > setup while reading the header, its just top that needs to explicitely > read it at tool start. > > Reported-by: John Garry <john.garry@huawei.com> > Analysed-by: Jiri Olsa <jolsa@kernel.org> > Cc: Adrian Hunter <adrian.hunter@intel.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Namhyung Kim <namhyung@kernel.org> > Cc: Will Deacon <will@kernel.org> > Link: https://lkml.kernel.org/n/tip-lxwjr0cd2eggzx04a780ffrv@git.kernel.org > Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> > --- > tools/perf/builtin-top.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c > index dc80044bc46f..795e353de095 100644 > --- a/tools/perf/builtin-top.c > +++ b/tools/perf/builtin-top.c > @@ -1568,9 +1568,13 @@ int cmd_top(int argc, const char **argv) > */ > status = perf_env__read_cpuid(&perf_env); > if (status) { > - pr_err("Couldn't read the cpuid for this machine: %s\n", > - str_error_r(errno, errbuf, sizeof(errbuf))); > - goto out_delete_evlist; > + /* > + * Some arches do not provide a get_cpuid(), so just use pr_debug, otherwise > + * warn the user explicitely. > + */ > + eprintf(status == ENOSYS ? 1 : 0, verbose, > + "Couldn't read the cpuid for this machine: %s\n", > + str_error_r(errno, errbuf, sizeof(errbuf))); > } > top.evlist->env = &perf_env; > > -- > 2.21.0 >
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