Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752694AbbEOEPZ (ORCPT ); Fri, 15 May 2015 00:15:25 -0400 Received: from e28smtp08.in.ibm.com ([122.248.162.8]:33535 "EHLO e28smtp08.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752416AbbEOEPU (ORCPT ); Fri, 15 May 2015 00:15:20 -0400 From: Hemant Kumar To: linux-kernel@vger.kernel.org Cc: maddy@linux.vnet.ibm.com, srikar@linux.vnet.ibm.com, mpe@ellerman.id.au, agraf@suse.de, kvm-ppc@vger.kernel.org, paulus@samba.org, warrier@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, acme@kernel.org, mingo@redhat.com, peterz@infradead.org, Hemant Kumar Subject: [RFC PATCH 1/1] perf/script: Script to display the ganged exits count on powerpc Date: Fri, 15 May 2015 09:44:26 +0530 Message-Id: <1431663266-13954-2-git-send-email-hemant@linux.vnet.ibm.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1431663266-13954-1-git-send-email-hemant@linux.vnet.ibm.com> References: <1431663266-13954-1-git-send-email-hemant@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15051504-0029-0000-0000-000005E90564 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4296 Lines: 119 In powerpc, when a thread running in the guest context needs to exit to the hypervisor to serve interrupts like the external interrupt, or the hcall interrupt, etc, all the threads running in that specific vcore inside the guest exit. These events can be classified as gang exits which mean that they are forced exits. Only if the other vcpus cede, then it won't be counted as a ganged exit. What this script does is, it post processes the perf.data file to look for two events : kvm_hv:kvmppc_run_core and kvm_hv:kvm_guest_exit. For a kvm_hv:kvmppc_run_core tracepoint event, it initializes : - if its an 'Entry', it gets the tgid and for that tgid, it initializes gang-exit count and cedes count. - if its an 'Exit', it gets the runnable thread count and subtracts it from the no of cedes to see (if) how many runnable threads were in that core and how many of them ceded. If the difference is more than 1 (its 1 because, we have to exclude the running thread itself), then its a ganged exit. For a kvm_hv:kvm_guest_exit event, it checks if the vcpu ceded. If it ceded, then increment the counter for cedes. Usage : # perf record -e kvm_hv:kvm_guest_exit -e kvm_hv:kvmppc_run_core -a sleep 10 [ perf record: Woken up 96 times to write data ] [ perf record: Captured and wrote 26.198 MB perf.data (~1144590 samples)] # perf script -s gang-exits.py Ganged exits summary Ganged exits for process 14000 : 535 Ganged exits for process 13988 : 25314 ======================================= Signed-off-by: Hemant Kumar --- tools/perf/scripts/python/gang_exits.py | 65 +++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 tools/perf/scripts/python/gang_exits.py diff --git a/tools/perf/scripts/python/gang_exits.py b/tools/perf/scripts/python/gang_exits.py new file mode 100644 index 0000000..011aa56 --- /dev/null +++ b/tools/perf/scripts/python/gang_exits.py @@ -0,0 +1,65 @@ +# gang-exits.py: Count the ganged exits of a VM +# +# In case of powerpc, When a thread running inside a guest needs to exit to +# the hypervisor to serve interrupts like the external interrupt, or the hcall +# interrupts, etc., all the threads running in that specific vcore +# inside the guest exit to the host. These events are called as ganged exits. +# These exits are forced. Only if the vcpus cede, then it/they won't be counted +# as ganged exit(s). +# +# Usage : +# So, if in powerpc, first we do : +# perf record -e kvm_hv:kvm_guest_exit -e kvm_hv:kvmppc_run_core -aR sleep +# Using the perf.data, we have to do : +# perf script -s gang-exits + +import os +import sys + +sys.path.append(os.environ['PERF_EXEC_PATH'] + \ + '/scripts/python/Perf-Trace-Util/lib/Perf/Trace') + +from perf_trace_context import * +from Core import * + +usage = "perf script -s gang_exits.py\n"; + +stats = {} +pid_tgid = {} + +def trace_begin(): + print "Ganged exits summary" + +def trace_end(): + print_ganged_exits() + +def kvm_hv__kvm_guest_exit(event_name, context, common_cpu, + common_secs, common_nsecs, common_pid, common_comm, + vcpu_id, reason, nip, msr, ceded): + + if common_pid in pid_tgid: + if ceded: # vcpu ceded ? + stats[pid_tgid[common_pid]]['nr_cedes'] += ceded + +def kvm_hv__kvmppc_run_core(event_name, context, common_cpu, + common_secs, common_nsecs, common_pid, common_comm, + n_runnable, runner_vcpu, where, tgid): + + if (where): # kvmppc_run_core: Exit + if tgid in stats: + forced = n_runnable - stats[tgid]['nr_cedes'] + if (forced > 1): + stats[tgid]['gang-exits'] += 1 + else: # kvmppc_run_core: Enter, init the counts + if tgid in stats: + stats[tgid]['nr_cedes'] = 0 + else: + stats[tgid] = {'gang-exits': 0, 'nr_cedes': 0} + if common_pid not in pid_tgid: + pid_tgid[common_pid] = tgid + +def print_ganged_exits(): + for i in stats.keys(): + print "\nGanged exits for process %d : %20d" %(i, stats[i]['gang-exits']) + + print "=======================================" -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/