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-rw-r--r--src/plugins/perfmon/dispatch_wrapper.c121
1 files changed, 76 insertions, 45 deletions
diff --git a/src/plugins/perfmon/dispatch_wrapper.c b/src/plugins/perfmon/dispatch_wrapper.c
index fe0a449df99..f5972f667a2 100644
--- a/src/plugins/perfmon/dispatch_wrapper.c
+++ b/src/plugins/perfmon/dispatch_wrapper.c
@@ -25,42 +25,64 @@
#include <perfmon/perfmon.h>
+static_always_inline u64
+perfmon_mmap_read_pmc1 (const struct perf_event_mmap_page *mmap_page)
+{
+ u64 count;
+ u32 seq;
+
+ /* See documentation in /usr/include/linux/perf_event.h, for more details
+ * but the 2 main important things are:
+ * 1) if seq != mmap_page->lock, it means the kernel is currently updating
+ * the user page and we need to read it again
+ * 2) if idx == 0, it means the perf event is currently turned off and we
+ * just need to read the kernel-updated 'offset', otherwise we must also
+ * add the current hw value (hence rdmpc) */
+ do
+ {
+ u32 idx;
+
+ seq = mmap_page->lock;
+ CLIB_COMPILER_BARRIER ();
+
+ idx = mmap_page->index;
+ count = mmap_page->offset;
+ if (idx)
+ count += _rdpmc (idx - 1);
+
+ CLIB_COMPILER_BARRIER ();
+ }
+ while (mmap_page->lock != seq);
+
+ return count;
+}
+
static_always_inline void
-perfmon_read_pmcs (u64 *counters, int *pmc_index, u8 n_counters)
+perfmon_mmap_read_pmcs (u64 *counters,
+ struct perf_event_mmap_page **mmap_pages,
+ u8 n_counters)
{
switch (n_counters)
{
default:
case 7:
- counters[6] = _rdpmc (pmc_index[6]);
+ counters[6] = perfmon_mmap_read_pmc1 (mmap_pages[6]);
case 6:
- counters[5] = _rdpmc (pmc_index[5]);
+ counters[5] = perfmon_mmap_read_pmc1 (mmap_pages[5]);
case 5:
- counters[4] = _rdpmc (pmc_index[4]);
+ counters[4] = perfmon_mmap_read_pmc1 (mmap_pages[4]);
case 4:
- counters[3] = _rdpmc (pmc_index[3]);
+ counters[3] = perfmon_mmap_read_pmc1 (mmap_pages[3]);
case 3:
- counters[2] = _rdpmc (pmc_index[2]);
+ counters[2] = perfmon_mmap_read_pmc1 (mmap_pages[2]);
case 2:
- counters[1] = _rdpmc (pmc_index[1]);
+ counters[1] = perfmon_mmap_read_pmc1 (mmap_pages[1]);
case 1:
- counters[0] = _rdpmc (pmc_index[0]);
+ counters[0] = perfmon_mmap_read_pmc1 (mmap_pages[0]);
break;
}
}
-static_always_inline int
-perfmon_calc_mmap_offset (perfmon_thread_runtime_t *tr, u8 i)
-{
- return (int) (tr->mmap_pages[i]->index + tr->mmap_pages[i]->offset);
-}
-
-static_always_inline int
-perfmon_metric_index (perfmon_bundle_t *b, u8 i)
-{
- return (int) (b->metrics[i]);
-}
-
uword
perfmon_dispatch_wrapper_mmap (vlib_main_t *vm, vlib_node_runtime_t *node,
vlib_frame_t *frame)
@@ -75,34 +97,13 @@ perfmon_dispatch_wrapper_mmap (vlib_main_t *vm, vlib_node_runtime_t *node,
u64 before[PERF_MAX_EVENTS];
u64 after[PERF_MAX_EVENTS];
- int pmc_index[PERF_MAX_EVENTS];
uword rv;
clib_prefetch_load (s);
- switch (n_events)
- {
- default:
- case 7:
- pmc_index[6] = perfmon_calc_mmap_offset (rt, 6);
- case 6:
- pmc_index[5] = perfmon_calc_mmap_offset (rt, 5);
- case 5:
- pmc_index[4] = perfmon_calc_mmap_offset (rt, 4);
- case 4:
- pmc_index[3] = perfmon_calc_mmap_offset (rt, 3);
- case 3:
- pmc_index[2] = perfmon_calc_mmap_offset (rt, 2);
- case 2:
- pmc_index[1] = perfmon_calc_mmap_offset (rt, 1);
- case 1:
- pmc_index[0] = perfmon_calc_mmap_offset (rt, 0);
- break;
- }
-
- perfmon_read_pmcs (&before[0], pmc_index, n_events);
+ perfmon_mmap_read_pmcs (&before[0], rt->mmap_pages, n_events);
rv = node->function (vm, node, frame);
- perfmon_read_pmcs (&after[0], pmc_index, n_events);
+ perfmon_mmap_read_pmcs (&after[0], rt->mmap_pages, n_events);
if (rv == 0)
return rv;
@@ -116,6 +117,36 @@ perfmon_dispatch_wrapper_mmap (vlib_main_t *vm, vlib_node_runtime_t *node,
return rv;
}
+static_always_inline void
+perfmon_metric_read_pmcs (u64 *counters, int *pmc_index, u8 n_counters)
+{
+ switch (n_counters)
+ {
+ default:
+ case 7:
+ counters[6] = _rdpmc (pmc_index[6]);
+ case 6:
+ counters[5] = _rdpmc (pmc_index[5]);
+ case 5:
+ counters[4] = _rdpmc (pmc_index[4]);
+ case 4:
+ counters[3] = _rdpmc (pmc_index[3]);
+ case 3:
+ counters[2] = _rdpmc (pmc_index[2]);
+ case 2:
+ counters[1] = _rdpmc (pmc_index[1]);
+ case 1:
+ counters[0] = _rdpmc (pmc_index[0]);
+ break;
+ }
+}
+
+static_always_inline int
+perfmon_metric_index (perfmon_bundle_t *b, u8 i)
+{
+ return (int) (b->metrics[i]);
+}
+
uword
perfmon_dispatch_wrapper_metrics (vlib_main_t *vm, vlib_node_runtime_t *node,
vlib_frame_t *frame)
@@ -154,11 +185,11 @@ perfmon_dispatch_wrapper_metrics (vlib_main_t *vm, vlib_node_runtime_t *node,
break;
}
- perfmon_read_pmcs (&before[0], pmc_index, n_events);
+ perfmon_metric_read_pmcs (&before[0], pmc_index, n_events);
rv = node->function (vm, node, frame);
clib_memcpy_fast (&s->t[0].value[0], &before, sizeof (before));
- perfmon_read_pmcs (&s->t[1].value[0], pmc_index, n_events);
+ perfmon_metric_read_pmcs (&s->t[1].value[0], pmc_index, n_events);
if (rv == 0)
return rv;