Merge branch 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf_counter: Start documenting HAVE_PERF_COUNTERS requirements
  perf_counter: Add forward/backward attribute ABI compatibility
  perf record: Explicity program a default counter
  perf_counter: Remove PERF_TYPE_RAW special casing
  perf_counter: PERF_TYPE_HW_CACHE is a hardware counter too
  powerpc, perf_counter: Fix performance counter event types
  perf_counter/x86: Add a quirk for Atom processors
  perf_counter tools: Remove one L1-data alias

4 files changed, 24 insertions, 5 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 29259e74dcfa..0f5771f615da 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -568,8 +568,11 @@ int cmd_record(int argc, const char **argv, const char *prefix)
         if (!argc && target_pid == -1 && !system_wide)
                 usage_with_options(record_usage, options);
 
-        if (!nr_counters)
-                nr_counters = 1;
+        if (!nr_counters) {
+                nr_counters     = 1;
+                attrs[0].type   = PERF_TYPE_HARDWARE;
+                attrs[0].config = PERF_COUNT_HW_CPU_CYCLES;
+        }
 
         for (counter = 0; counter < nr_counters; counter++) {
                 if (attrs[counter].sample_period)
diff --git a/tools/perf/design.txt b/tools/perf/design.txt
index 860e116d979c..f71e0d245cba 100644
--- a/tools/perf/design.txt
+++ b/tools/perf/design.txt
@@ -440,3 +440,18 @@ by this process or by another, and doesn't affect any counters that
 this process has created on other processes.  It only enables or
 disables the group leaders, not any other members in the groups.
 
+
+Arch requirements
+-----------------
+
+If your architecture does not have hardware performance metrics, you can
+still use the generic software counters based on hrtimers for sampling.
+
+So to start with, in order to add HAVE_PERF_COUNTERS to your Kconfig, you
+will need at least this:
+        - asm/perf_counter.h - a basic stub will suffice at first
+        - support for atomic64 types (and associated helper functions)
+        - set_perf_counter_pending() implemented
+
+If your architecture does have hardware capabilities, you can override the
+weak stub hw_perf_counter_init() to register hardware counters.
diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index af0a5046d743..87a1aca4a424 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -53,11 +53,12 @@ static inline unsigned long long rdclock(void)
         _min1 < _min2 ? _min1 : _min2; })
 
 static inline int
-sys_perf_counter_open(struct perf_counter_attr *attr_uptr,
+sys_perf_counter_open(struct perf_counter_attr *attr,
                       pid_t pid, int cpu, int group_fd,
                       unsigned long flags)
 {
-        return syscall(__NR_perf_counter_open, attr_uptr, pid, cpu,
+        attr->size = sizeof(*attr);
+        return syscall(__NR_perf_counter_open, attr, pid, cpu,
                        group_fd, flags);
 }
 
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 9d5f1ca50e6f..5a72586e1df0 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -75,7 +75,7 @@ static char *sw_event_names[] = {
 #define MAX_ALIASES 8
 
 static char *hw_cache [][MAX_ALIASES] = {
-        { "L1-data"             , "l1-d", "l1d", "l1"                           },
+        { "L1-data"             , "l1-d", "l1d"                                 },
         { "L1-instruction"      , "l1-i", "l1i"                                 },
         { "L2"                  , "l2"                                          },
         { "Data-TLB"            , "dtlb", "d-tlb"                               },