perf tools: Add the ability to specify list of cpus to monitor

This patch adds a -C option to stat, record, top to designate a list of CPUs to
monitor. CPUs can be specified as a comma-separated list or ranges, no space
allowed.

Examples:
$ perf record -a -C0-1,4-7 sleep 1
$ perf top -C0-4
$ perf stat -a -C1,2,3,4 sleep 1

With perf record in per-thread mode with inherit mode on, samples are collected
only when the thread runs on the designated CPUs.

The -C option does not turn on system-wide mode automatically.

Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <4bff9496.d345d80a.41fe.7b00@mx.google.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

8 files changed, 110 insertions, 24 deletions

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 34e255fc3e2f..25576b477c83 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -103,6 +103,13 @@ OPTIONS
 --raw-samples::
 Collect raw sample records from all opened counters (default for tracepoint counters).
 
+-C::
+--cpu::
+Collect samples only on the list of cpus provided. Multiple CPUs can be provided as a
+comma-sperated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
+In per-thread mode with inheritance mode on (default), samples are captured only when
+the thread executes on the designated CPUs. Default is to monitor all CPUs.
+
 SEE ALSO
 --------
 linkperf:perf-stat[1], linkperf:perf-list[1]
diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 909fa766fa1c..4b3a2d46b437 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -46,6 +46,13 @@ OPTIONS
 -B::
         print large numbers with thousands' separators according to locale
 
+-C::
+--cpu=::
+Count only on the list of cpus provided. Multiple CPUs can be provided as a
+comma-sperated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
+In per-thread mode, this option is ignored. The -a option is still necessary
+to activate system-wide monitoring. Default is to count on all CPUs.
+
 EXAMPLES
 --------
 
diff --git a/tools/perf/Documentation/perf-top.txt b/tools/perf/Documentation/perf-top.txt
index 785b9fc32a46..1f9687663f2a 100644
--- a/tools/perf/Documentation/perf-top.txt
+++ b/tools/perf/Documentation/perf-top.txt
@@ -25,9 +25,11 @@ OPTIONS
 --count=<count>::
         Event period to sample.
 
--C <cpu>::
---CPU=<cpu>::
-        CPU to profile.
+-C <cpu-list>::
+--cpu=<cpu>::
+Monitor only on the list of cpus provided. Multiple CPUs can be provided as a
+comma-sperated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
+Default is to monitor all CPUS.
 
 -d <seconds>::
 --delay=<seconds>::
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index dc3435e18bde..f28c4bbd801f 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -49,7 +49,6 @@ static int			group				=      0;
 static int                      realtime_prio                   =      0;
 static bool                     raw_samples                     =  false;
 static bool                     system_wide                     =  false;
-static int                      profile_cpu                     =     -1;
 static pid_t                    target_pid                      =     -1;
 static pid_t                    target_tid                      =     -1;
 static pid_t                    *all_tids                       =      NULL;
@@ -74,6 +73,7 @@ static int			file_new			=      1;
 static off_t                    post_processing_offset;
 
 static struct perf_session      *session;
+static const char               *cpu_list;
 
 struct mmap_data {
         int                     counter;
@@ -300,7 +300,7 @@ try_again:
                                 die("Permission error - are you root?\n"
                                         "\t Consider tweaking"
                                         " /proc/sys/kernel/perf_event_paranoid.\n");
-                        else if (err ==  ENODEV && profile_cpu != -1) {
+                        else if (err ==  ENODEV && cpu_list) {
                                 die("No such device - did you specify"
                                         " an out-of-range profile CPU?\n");
                         }
@@ -622,10 +622,15 @@ static int __cmd_record(int argc, const char **argv)
                 close(child_ready_pipe[0]);
         }
 
-        if ((!system_wide && no_inherit) || profile_cpu != -1) {
-                open_counters(profile_cpu);
+        nr_cpus = read_cpu_map(cpu_list);
+        if (nr_cpus < 1) {
+                perror("failed to collect number of CPUs\n");
+                return -1;
+        }
+
+        if (!system_wide && no_inherit && !cpu_list) {
+                open_counters(-1);
         } else {
-                nr_cpus = read_cpu_map();
                 for (i = 0; i < nr_cpus; i++)
                         open_counters(cpumap[i]);
         }
@@ -704,7 +709,7 @@ static int __cmd_record(int argc, const char **argv)
         if (perf_guest)
                 perf_session__process_machines(session, event__synthesize_guest_os);
 
-        if (!system_wide && profile_cpu == -1)
+        if (!system_wide && cpu_list)
                 event__synthesize_thread(target_tid, process_synthesized_event,
                                          session);
         else
@@ -794,8 +799,8 @@ static const struct option options[] = {
                             "system-wide collection from all CPUs"),
         OPT_BOOLEAN('A', "append", &append_file,
                             "append to the output file to do incremental profiling"),
-        OPT_INTEGER('C', "profile_cpu", &profile_cpu,
-                            "CPU to profile on"),
+        OPT_STRING('C', "cpu", &cpu_list, "cpu",
+                    "list of cpus to monitor"),
         OPT_BOOLEAN('f', "force", &force,
                         "overwrite existing data file (deprecated)"),
         OPT_U64('c', "count", &user_interval, "event period to sample"),
@@ -825,7 +830,7 @@ int cmd_record(int argc, const char **argv, const char *prefix __used)
         argc = parse_options(argc, argv, options, record_usage,
                             PARSE_OPT_STOP_AT_NON_OPTION);
         if (!argc && target_pid == -1 && target_tid == -1 &&
-                !system_wide && profile_cpu == -1)
+                !system_wide && !cpu_list)
                 usage_with_options(record_usage, options);
 
         if (force && append_file) {
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 9a39ca3c3ac4..a6b4d44f9502 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -69,7 +69,7 @@ static struct perf_event_attr default_attrs[] = {
 };
 
 static bool                     system_wide                     =  false;
-static unsigned int             nr_cpus                         =  0;
+static int                      nr_cpus                         =  0;
 static int                      run_idx                         =  0;
 
 static int                      run_count                       =  1;
@@ -82,6 +82,7 @@ static int			thread_num			=  0;
 static pid_t                    child_pid                       = -1;
 static bool                     null_run                        =  false;
 static bool                     big_num                         =  false;
+static const char               *cpu_list;
 
 
 static int                      *fd[MAX_NR_CPUS][MAX_COUNTERS];
@@ -158,7 +159,7 @@ static int create_perf_stat_counter(int counter)
                                     PERF_FORMAT_TOTAL_TIME_RUNNING;
 
         if (system_wide) {
-                unsigned int cpu;
+                int cpu;
 
                 for (cpu = 0; cpu < nr_cpus; cpu++) {
                         fd[cpu][counter][0] = sys_perf_event_open(attr,
@@ -208,7 +209,7 @@ static inline int nsec_counter(int counter)
 static void read_counter(int counter)
 {
         u64 count[3], single_count[3];
-        unsigned int cpu;
+        int cpu;
         size_t res, nv;
         int scaled;
         int i, thread;
@@ -542,6 +543,8 @@ static const struct option options[] = {
                     "null run - dont start any counters"),
         OPT_BOOLEAN('B', "big-num", &big_num,
                     "print large numbers with thousands\' separators"),
+        OPT_STRING('C', "cpu", &cpu_list, "cpu",
+                    "list of cpus to monitor in system-wide"),
         OPT_END()
 };
 
@@ -566,10 +569,13 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
         }
 
         if (system_wide)
-                nr_cpus = read_cpu_map();
+                nr_cpus = read_cpu_map(cpu_list);
         else
                 nr_cpus = 1;
 
+        if (nr_cpus < 1)
+                usage_with_options(stat_usage, options);
+
         if (target_pid != -1) {
                 target_tid = target_pid;
                 thread_num = find_all_tid(target_pid, &all_tids);
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index a66f4272b994..45014ef11059 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -102,6 +102,7 @@ struct sym_entry		*sym_filter_entry_sched		=   NULL;
 static int                      sym_pcnt_filter                 =      5;
 static int                      sym_counter                     =      0;
 static int                      display_weighted                =     -1;
+static const char               *cpu_list;
 
 /*
  * Symbols
@@ -1351,8 +1352,8 @@ static const struct option options[] = {
                     "profile events on existing thread id"),
         OPT_BOOLEAN('a', "all-cpus", &system_wide,
                             "system-wide collection from all CPUs"),
-        OPT_INTEGER('C', "CPU", &profile_cpu,
-                    "CPU to profile on"),
+        OPT_STRING('C', "cpu", &cpu_list, "cpu",
+                    "list of cpus to monitor"),
         OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
                    "file", "vmlinux pathname"),
         OPT_BOOLEAN('K', "hide_kernel_symbols", &hide_kernel_symbols,
@@ -1428,10 +1429,10 @@ int cmd_top(int argc, const char **argv, const char *prefix __used)
                 return -ENOMEM;
 
         /* CPU and PID are mutually exclusive */
-        if (target_tid > 0 && profile_cpu != -1) {
+        if (target_tid > 0 && cpu_list) {
                 printf("WARNING: PID switch overriding CPU\n");
                 sleep(1);
-                profile_cpu = -1;
+                cpu_list = NULL;
         }
 
         if (!nr_counters)
@@ -1469,10 +1470,13 @@ int cmd_top(int argc, const char **argv, const char *prefix __used)
                 attrs[counter].sample_period = default_interval;
         }
 
-        if (target_tid != -1 || profile_cpu != -1)
+        if (target_tid != -1)
                 nr_cpus = 1;
         else
-                nr_cpus = read_cpu_map();
+                nr_cpus = read_cpu_map(cpu_list);
+
+        if (nr_cpus < 1)
+                usage_with_options(top_usage, options);
 
         get_term_dimensions(&winsize);
         if (print_entries == 0) {
diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
index 4e01490e51e5..0f9b8d7a7d7e 100644
--- a/tools/perf/util/cpumap.c
+++ b/tools/perf/util/cpumap.c
@@ -20,7 +20,7 @@ static int default_cpu_map(void)
         return nr_cpus;
 }
 
-int read_cpu_map(void)
+static int read_all_cpu_map(void)
 {
         FILE *onlnf;
         int nr_cpus = 0;
@@ -57,3 +57,58 @@ int read_cpu_map(void)
 
         return default_cpu_map();
 }
+
+int read_cpu_map(const char *cpu_list)
+{
+        unsigned long start_cpu, end_cpu = 0;
+        char *p = NULL;
+        int i, nr_cpus = 0;
+
+        if (!cpu_list)
+                return read_all_cpu_map();
+
+        if (!isdigit(*cpu_list))
+                goto invalid;
+
+        while (isdigit(*cpu_list)) {
+                p = NULL;
+                start_cpu = strtoul(cpu_list, &p, 0);
+                if (start_cpu >= INT_MAX
+                    || (*p != '\0' && *p != ',' && *p != '-'))
+                        goto invalid;
+
+                if (*p == '-') {
+                        cpu_list = ++p;
+                        p = NULL;
+                        end_cpu = strtoul(cpu_list, &p, 0);
+
+                        if (end_cpu >= INT_MAX || (*p != '\0' && *p != ','))
+                                goto invalid;
+
+                        if (end_cpu < start_cpu)
+                                goto invalid;
+                } else {
+                        end_cpu = start_cpu;
+                }
+
+                for (; start_cpu <= end_cpu; start_cpu++) {
+                        /* check for duplicates */
+                        for (i = 0; i < nr_cpus; i++)
+                                if (cpumap[i] == (int)start_cpu)
+                                        goto invalid;
+
+                        assert(nr_cpus < MAX_NR_CPUS);
+                        cpumap[nr_cpus++] = (int)start_cpu;
+                }
+                if (*p)
+                        ++p;
+
+                cpu_list = p;
+        }
+        if (nr_cpus > 0)
+                return nr_cpus;
+
+        return default_cpu_map();
+invalid:
+        return -1;
+}
diff --git a/tools/perf/util/cpumap.h b/tools/perf/util/cpumap.h
index 86c78bb33098..3e60f56e490e 100644
--- a/tools/perf/util/cpumap.h
+++ b/tools/perf/util/cpumap.h
@@ -1,7 +1,7 @@
 #ifndef __PERF_CPUMAP_H
 #define __PERF_CPUMAP_H
 
-extern int read_cpu_map(void);
+extern int read_cpu_map(const char *cpu_list);
 extern int cpumap[];
 
 #endif /* __PERF_CPUMAP_H */