Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751799AbcCXVPk (ORCPT ); Thu, 24 Mar 2016 17:15:40 -0400 Received: from mail.kernel.org ([198.145.29.136]:42758 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751038AbcCXVPf (ORCPT ); Thu, 24 Mar 2016 17:15:35 -0400 Date: Thu, 24 Mar 2016 18:15:28 -0300 From: Arnaldo Carvalho de Melo To: Ravi Bangoria Cc: linux-kernel@vger.kernel.org, hemant@linux.vnet.ibm.com, naveen.n.rao@linux.vnet.ibm.com Subject: Re: [RFC 1/4] perf kvm: Enable 'record' on powerpc Message-ID: <20160324211528.GD32162@kernel.org> References: <1456304865-15131-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com> <1456304865-15131-2-git-send-email-ravi.bangoria@linux.vnet.ibm.com> <20160322191211.GD25862@kernel.org> <20160323021921.GE25862@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160323021921.GE25862@kernel.org> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9920 Lines: 273 Em Tue, Mar 22, 2016 at 11:19:21PM -0300, Arnaldo Carvalho de Melo escreveu: > Em Tue, Mar 22, 2016 at 04:12:11PM -0300, Arnaldo Carvalho de Melo escreveu: > > Em Wed, Feb 24, 2016 at 02:37:42PM +0530, Ravi Bangoria escreveu: > > > 'perf kvm record' is not available on powerpc because 'perf' relies on > > > the 'cycles' event (a PMU event) to profile the guest. However, for > > > powerpc, this can't be used from the host because the PMUs are controlled > > > by the guest rather than the host. > > > > > > There exists a tracepoint 'kvm_hv:kvm_guest_exit' in powerpc which is > > > hit whenever any of the threads exit the guest context. The guest > > > instruction pointer dumped along with this tracepoint data in the field > > > 'pc', can be used as guest instruction pointer. > > > > > > This patch changes default event as kvm_hv:kvm_guest_exit for recording > > > guest data in host on powerpc. As we are using host event to record guest > > > data, this approach will enable only --guest option of 'perf kvm'. Still > > > --host --guest together won't work. > > > > It should, i.e. --host --guest should translate to: > > > > -e cycles:H,kvm_hv:kvm_guest_exit > > > > I.e. both collect cycles only in the host, and also the tracepoint that > > will allow us to get the guest approximation for the unavailable cycles > > event, no? > > > > I'm putting the infrastructure work needed for this the perf/cpumode > > branch. More work will be put there soon. > > So I took a different path and made perf_evsel__parse_sample set a new > perf_sample.cpumode field, this way we'll end up having just to set a > per-evsel ->post_parse_sample() callback for the event that replaces > "cycles" for PPC guests where we'll just set data->ip and data->cpumode, > the rest of the code remains unchanged. > > The changes I made looks useful in itself, as, IIRC more code was > removed than added. > > I'll continue tomorrow and will test with the kvm:kvm_exit on x86_64 for > testing, that has: Ok, so the infrastructure got merged already and from there the next steps are in running with: perf kvm --guest record -a -e cycles:H,kvm:kvm_exit And then, with the patch below applied, try: perf kvm --guestkallsyms kallsyms.guest --guestmodules modules.guest report -i perf.data.guest --munge-ppc-guest-sample kvm:kvm_exit I'm almost there, it is still not resolving to the kernel DSO, etc, so I get: Samples: 1K of event 'kvm:kvm_exit', Event count (approx.): 1924 Overhead Command Shared Object Symbol 34.77% :5343 [unknown] [g] 0xffffffff81043158 16.84% :5345 [unknown] [g] 0xffffffff813f3d5a 16.84% :5345 [unknown] [g] 0xffffffff813f43ec 13.83% :5345 [unknown] [g] 0xffffffff81043158 9.62% :5343 [unknown] [g] 0xffffffff8104301a 3.79% :5345 [unknown] [g] 0xffffffff8104301a 1.77% :5345 [unknown] [u] 0x0000003ae6c75dc9 0.52% :5343 [unknown] [g] 0xffffffff812a29b1 0.16% :5343 [unknown] [g] 0xffffffff8100bc00 0.10% :5343 [unknown] [g] 0xffffffff8104315a 0.10% :5343 [unknown] [g] 0xffffffff8106306f 0.10% :5343 [unknown] [g] 0xffffffff8153b7fc 0.10% :5345 [unknown] [g] 0xffffffff8106306f 0.05% :5343 [unknown] [g] 0xffffffff8100b720 [root@jouet ~]# cat /proc/*/task/5343/comm qemu-system-x86 [root@jouet ~]# The patch does several of the things you did per sample, but only right after opening the perf.data file, and I'll break it down in multiple patches, this is just a heads up, please review it if you have the time, in the end we should have a mechanism useful not just for PPC and that affects just 'perf kvm' in this specific case. - Arnaldo diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c index bff666458b28..b7b6527446f8 100644 --- a/tools/perf/builtin-kvm.c +++ b/tools/perf/builtin-kvm.c @@ -1480,6 +1480,86 @@ perf_stat: } #endif /* HAVE_KVM_STAT_SUPPORT */ +#ifdef __powerpc__ +#define PPC_HV_DECREMENTER 2432 +#define PPC_HV_BIT 3 +#define PPC_PR_BIT 49 +#define PPC_MAX 63 + +static bool perf_sample__is_hv_dec_trap(struct perf_sample *sample, struct perf_evsel *evsel) +{ + int trap = perf_evsel__intval(evsel, sample, "trap"); + return trap == PPC_HV_DECREMENTER; +} + +static void perf_kvm__munge_ppc_guest_sample(struct perf_evsel *evsel, struct perf_sample *sample) +{ + unsigned long msr, hv, pr; + + if (!perf_sample__is_hv_dec_trap(sample, evsel)) + return; + + sample->ip = perf_evsel__intval(evsel, sample, "pc"); + sample->cpumode = PERF_RECORD_MISC_GUEST_KERNEL; + + msr = perf_evsel__intval(evsel, sample, "msr"); + hv = msr & ((unsigned long)1 << (PPC_MAX - PPC_HV_BIT)); + pr = msr & ((unsigned long)1 << (PPC_MAX - PPC_PR_BIT)); + if (!hv && pr) + sample->cpumode = PERF_RECORD_MISC_GUEST_USER; +} + +static bool perf_evlist__recorded_on_ppc(const struct perf_evlist *evlist) +{ + if (evlist->env && evlist->env->arch) { + return !strcmp(evlist->env->arch, "ppc64") || + !strcmp(evlist->env->arch, "ppc64le"); + } + return false; +} +#elif defined(__i386__) || defined(__x86_64__) +/* + * For testing with kvm:kvm_exit + */ +static void perf_kvm__munge_ppc_guest_sample(struct perf_evsel *evsel, struct perf_sample *sample) +{ + sample->ip = perf_evsel__intval(evsel, sample, "guest_rip"); + sample->cpumode = PERF_RECORD_MISC_GUEST_KERNEL; + + if (sample->ip < 0xffffffff00000000) + sample->cpumode = PERF_RECORD_MISC_GUEST_USER; + + if (0) { + fprintf(stderr, "%s: %s, cpumode=%d ip=%" PRIx64 "\n", + __func__, perf_evsel__name(evsel), sample->cpumode, sample->ip); + } +} + +static bool perf_evlist__recorded_on_ppc(const struct perf_evlist *evlist __maybe_unused) +{ + return true; +} +#endif + +int perf_kvm__setup_munge_ppc_guest_event(struct perf_evlist *evlist, const char *name) +{ + struct perf_evsel *evsel; + + if (!perf_evlist__recorded_on_ppc(evlist)) + return 0; + + evsel = perf_evlist__find_tracepoint_by_name(evlist, name); + if (evsel == NULL) + return -1; + + if (0) + fprintf(stderr, "%s: %s\n", __func__, perf_evsel__name(evsel)); + + evsel->munge_sample = perf_kvm__munge_ppc_guest_sample; + + return 0; +} + static int __cmd_record(const char *file_name, int argc, const char **argv) { int rec_argc, i = 0, j; diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c index 160ea23b45aa..ba8786d12423 100644 --- a/tools/perf/builtin-report.c +++ b/tools/perf/builtin-report.c @@ -667,6 +667,7 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused) int branch_mode = -1; bool branch_call_mode = false; char callchain_default_opt[] = CALLCHAIN_DEFAULT_OPT; + const char *munge_ppc_guest_event = NULL; const char * const report_usage[] = { "perf report []", NULL @@ -814,6 +815,8 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused) "Show raw trace event output (do not use print fmt or plugins)"), OPT_BOOLEAN(0, "hierarchy", &symbol_conf.report_hierarchy, "Show entries in a hierarchy"), + OPT_STRING(0, "munge-ppc-guest-sample", &munge_ppc_guest_event, "event name", + "Use a different event to simulate guest cycles, not accessible on PPC hosts"), OPT_END() }; struct perf_data_file file = { @@ -880,6 +883,12 @@ repeat: if (session == NULL) return -1; + if (munge_ppc_guest_event && + perf_kvm__setup_munge_ppc_guest_event(session->evlist, munge_ppc_guest_event)) { + pr_err("PPC event not present in %s file\n", input_name); + goto error; + } + if (report.queue_size) { ordered_events__set_alloc_size(&session->ordered_events, report.queue_size); diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 738ce226002b..1665171a6e9c 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -216,6 +216,7 @@ void perf_evsel__init(struct perf_evsel *evsel, evsel->sample_size = __perf_evsel__sample_size(attr->sample_type); perf_evsel__calc_id_pos(evsel); evsel->cmdline_group_boundary = false; + evsel->munge_sample = NULL; } struct perf_evsel *perf_evsel__new_idx(struct perf_event_attr *attr, int idx) @@ -1887,6 +1888,9 @@ int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event, } } + if (evsel->munge_sample != NULL) + evsel->munge_sample(evsel, data); + return 0; } diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h index 501ea6e565f1..46379451f641 100644 --- a/tools/perf/util/evsel.h +++ b/tools/perf/util/evsel.h @@ -12,6 +12,7 @@ #include "counts.h" struct perf_evsel; +struct perf_sample; /* * Per fd, to map back from PERF_SAMPLE_ID to evsel, only used when there are @@ -92,6 +93,8 @@ struct perf_evsel { double scale; const char *unit; struct event_format *tp_format; + void (*munge_sample)(struct perf_evsel *evsel, + struct perf_sample *sample); off_t id_offset; void *priv; u64 db_id; @@ -236,8 +239,6 @@ int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus, struct thread_map *threads); void perf_evsel__close(struct perf_evsel *evsel, int ncpus, int nthreads); -struct perf_sample; - void *perf_evsel__rawptr(struct perf_evsel *evsel, struct perf_sample *sample, const char *name); u64 perf_evsel__intval(struct perf_evsel *evsel, struct perf_sample *sample, diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h index 8298d607c738..12bc51450d56 100644 --- a/tools/perf/util/util.h +++ b/tools/perf/util/util.h @@ -356,4 +356,9 @@ typedef void (*print_binary_t)(enum binary_printer_ops, void print_binary(unsigned char *data, size_t len, size_t bytes_per_line, print_binary_t printer, void *extra); + +struct perf_evlist; + +int perf_kvm__setup_munge_ppc_guest_event(struct perf_evlist *evlist, const char *name); + #endif /* GIT_COMPAT_UTIL_H */