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perfmon: refactor perf metric support

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Refactoring perf metric support to remove branching on bundle type in
the dispatch wrapper. This change includes caching the rdpmc index at
perfmon_start(), so that the mmap_page.index doesn't need to be looked
up each time. It also exclude the effects of mmap_page.index.

This patch prepares the path for bundles that support general, fixed and
metrics counters simulataneously.

Type: refactor

Signed-off-by: Ray Kinsella <mdr@ashroe.eu>
Change-Id: I9c5b4917bd02fea960e546e8558452c4362eabc4
This commit is contained in:
Ray Kinsella
2021-12-02 08:06:01 +00:00
committed by Damjan Marion
parent c30f3006bd
commit e893beab27
4 changed files with 82 additions and 191 deletions
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191
src/plugins/perfmon/dispatch_wrapper.c
View File

@@ -25,77 +25,41 @@
#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_mmap_read_pmcs (u64 *counters,
struct perf_event_mmap_page **mmap_pages,
u8 n_counters)
perfmon_read_pmcs (u64 *counters, u32 *indexes, u8 n_counters)
{
switch (n_counters)
{
default:
case 12:
counters[11] = perfmon_mmap_read_pmc1 (mmap_pages[11]);
counters[11] = _rdpmc (indexes[11] - 1);
case 11:
counters[10] = perfmon_mmap_read_pmc1 (mmap_pages[10]);
counters[10] = _rdpmc (indexes[10] - 1);
case 10:
counters[9] = perfmon_mmap_read_pmc1 (mmap_pages[9]);
counters[9] = _rdpmc (indexes[9] - 1);
case 9:
counters[8] = perfmon_mmap_read_pmc1 (mmap_pages[8]);
counters[8] = _rdpmc (indexes[8] - 1);
case 8:
counters[7] = perfmon_mmap_read_pmc1 (mmap_pages[7]);
counters[7] = _rdpmc (indexes[7] - 1);
case 7:
counters[6] = perfmon_mmap_read_pmc1 (mmap_pages[6]);
counters[6] = _rdpmc (indexes[6] - 1);
case 6:
counters[5] = perfmon_mmap_read_pmc1 (mmap_pages[5]);
counters[5] = _rdpmc (indexes[5] - 1);
case 5:
counters[4] = perfmon_mmap_read_pmc1 (mmap_pages[4]);
counters[4] = _rdpmc (indexes[4] - 1);
case 4:
counters[3] = perfmon_mmap_read_pmc1 (mmap_pages[3]);
counters[3] = _rdpmc (indexes[3] - 1);
case 3:
counters[2] = perfmon_mmap_read_pmc1 (mmap_pages[2]);
counters[2] = _rdpmc (indexes[2] - 1);
case 2:
counters[1] = perfmon_mmap_read_pmc1 (mmap_pages[1]);
counters[1] = _rdpmc (indexes[1] - 1);
case 1:
counters[0] = perfmon_mmap_read_pmc1 (mmap_pages[0]);
break;
counters[0] = _rdpmc (indexes[0] - 1);
}
}
uword
perfmon_dispatch_wrapper_mmap (vlib_main_t *vm, vlib_node_runtime_t *node,
vlib_frame_t *frame)
perfmon_dispatch_wrapper (vlib_main_t *vm, vlib_node_runtime_t *node,
vlib_frame_t *frame)
{
perfmon_main_t *pm = &perfmon_main;
perfmon_thread_runtime_t *rt =
@@ -105,15 +69,17 @@ perfmon_dispatch_wrapper_mmap (vlib_main_t *vm, vlib_node_runtime_t *node,
u8 n_events = rt->n_events;
u64 before[PERF_MAX_EVENTS];
u64 after[PERF_MAX_EVENTS];
struct
{
u64 t[2][PERF_MAX_EVENTS];
} samples;
uword rv;
clib_prefetch_load (s);
perfmon_mmap_read_pmcs (&before[0], rt->mmap_pages, n_events);
perfmon_read_pmcs (&samples.t[0][0], &rt->indexes[0], n_events);
rv = node->function (vm, node, frame);
perfmon_mmap_read_pmcs (&after[0], rt->mmap_pages, n_events);
perfmon_read_pmcs (&samples.t[1][0], &rt->indexes[0], n_events);
if (rv == 0)
return rv;
@@ -122,110 +88,17 @@ perfmon_dispatch_wrapper_mmap (vlib_main_t *vm, vlib_node_runtime_t *node,
s->n_packets += rv;
for (int i = 0; i < n_events; i++)
s->value[i] += after[i] - before[i];
return rv;
}
static_always_inline void
perfmon_metric_read_pmcs (u64 *counters, int *pmc_index, u8 n_counters)
{
switch (n_counters)
{
default:
case 12:
counters[11] = _rdpmc (pmc_index[11]);
case 11:
counters[10] = _rdpmc (pmc_index[10]);
case 10:
counters[9] = _rdpmc (pmc_index[9]);
case 9:
counters[8] = _rdpmc (pmc_index[8]);
case 8:
counters[7] = _rdpmc (pmc_index[7]);
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)
{
perfmon_main_t *pm = &perfmon_main;
perfmon_thread_runtime_t *rt =
vec_elt_at_index (pm->thread_runtimes, vm->thread_index);
perfmon_node_stats_t *s =
vec_elt_at_index (rt->node_stats, node->node_index);
u8 n_events = rt->n_events;
u64 before[PERF_MAX_EVENTS];
int pmc_index[PERF_MAX_EVENTS];
uword rv;
clib_prefetch_load (s);
switch (n_events)
{
default:
case 12:
pmc_index[11] = perfmon_metric_index (rt->bundle, 11);
case 11:
pmc_index[10] = perfmon_metric_index (rt->bundle, 10);
case 10:
pmc_index[9] = perfmon_metric_index (rt->bundle, 9);
case 9:
pmc_index[8] = perfmon_metric_index (rt->bundle, 8);
case 8:
pmc_index[7] = perfmon_metric_index (rt->bundle, 7);
case 7:
pmc_index[6] = perfmon_metric_index (rt->bundle, 6);
case 6:
pmc_index[5] = perfmon_metric_index (rt->bundle, 5);
case 5:
pmc_index[4] = perfmon_metric_index (rt->bundle, 4);
case 4:
pmc_index[3] = perfmon_metric_index (rt->bundle, 3);
case 3:
pmc_index[2] = perfmon_metric_index (rt->bundle, 2);
case 2:
pmc_index[1] = perfmon_metric_index (rt->bundle, 1);
case 1:
pmc_index[0] = perfmon_metric_index (rt->bundle, 0);
break;
}
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_metric_read_pmcs (&s->t[1].value[0], pmc_index, n_events);
if (rv == 0)
return rv;
s->n_calls += 1;
s->n_packets += rv;
{
if (!(rt->preserve_samples & 1 << i))
{
s->value[i] += samples.t[1][i] - samples.t[0][i];
}
else
{
s->t[0].value[i] = samples.t[0][i];
s->t[1].value[i] = samples.t[1][i];
}
}
return rv;
}

10
src/plugins/perfmon/intel/bundle/topdown_metrics.c
View File

@@ -122,16 +122,13 @@ PERFMON_REGISTER_BUNDLE (topdown_lvl1_metric) = {
.name = "topdown-level1",
.description = "Top-down Microarchitecture Analysis Level 1",
.source = "intel-core",
.offset_type = PERFMON_OFFSET_TYPE_METRICS,
.events[0] = INTEL_CORE_E_TOPDOWN_SLOTS,
.events[1] = INTEL_CORE_E_TOPDOWN_L1_RETIRING_METRIC,
.events[2] = INTEL_CORE_E_TOPDOWN_L1_BAD_SPEC_METRIC,
.events[3] = INTEL_CORE_E_TOPDOWN_L1_FE_BOUND_METRIC,
.events[4] = INTEL_CORE_E_TOPDOWN_L1_BE_BOUND_METRIC,
.n_events = 5,
.metrics[0] = RDPMC_SLOTS | FIXED_COUNTER_SLOTS,
.metrics[1] = RDPMC_METRICS | METRIC_COUNTER_TOPDOWN_L1_L2,
.n_metrics = 2,
.preserve_samples = 0x1F,
.cpu_supports = topdown_lvl1_cpu_supports,
.n_cpu_supports = ARRAY_LEN (topdown_lvl1_cpu_supports),
.format_fn = format_topdown_lvl1,
@@ -251,7 +248,6 @@ PERFMON_REGISTER_BUNDLE (topdown_lvl2_metric) = {
.name = "topdown-level2",
.description = "Top-down Microarchitecture Analysis Level 2",
.source = "intel-core",
.offset_type = PERFMON_OFFSET_TYPE_METRICS,
.events[0] = INTEL_CORE_E_TOPDOWN_SLOTS,
.events[1] = INTEL_CORE_E_TOPDOWN_L1_RETIRING_METRIC,
.events[2] = INTEL_CORE_E_TOPDOWN_L1_BAD_SPEC_METRIC,
@@ -262,9 +258,7 @@ PERFMON_REGISTER_BUNDLE (topdown_lvl2_metric) = {
.events[7] = INTEL_CORE_E_TOPDOWN_L2_FETCHLAT_METRIC,
.events[8] = INTEL_CORE_E_TOPDOWN_L2_MEMBOUND_METRIC,
.n_events = 9,
.metrics[0] = RDPMC_SLOTS | FIXED_COUNTER_SLOTS,
.metrics[1] = RDPMC_METRICS | METRIC_COUNTER_TOPDOWN_L1_L2,
.n_metrics = 2,
.preserve_samples = 0x1FF,
.cpu_supports = topdown_lvl2_cpu_supports,
.n_cpu_supports = ARRAY_LEN (topdown_lvl2_cpu_supports),
.format_fn = format_topdown_lvl2,

52
src/plugins/perfmon/perfmon.c
View File

@@ -196,6 +196,7 @@ perfmon_set (vlib_main_t *vm, perfmon_bundle_t *b)
rt->bundle = b;
rt->n_events = b->n_events;
rt->n_nodes = n_nodes;
rt->preserve_samples = b->preserve_samples;
vec_validate_aligned (rt->node_stats, n_nodes - 1,
CLIB_CACHE_LINE_BYTES);
}
@@ -212,6 +213,33 @@ error:
return err;
}
static_always_inline u32
perfmon_mmap_read_index (const struct perf_event_mmap_page *mmap_page)
{
u32 idx;
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
{
seq = mmap_page->lock;
CLIB_COMPILER_BARRIER ();
idx = mmap_page->index;
CLIB_COMPILER_BARRIER ();
}
while (mmap_page->lock != seq);
return idx;
}
clib_error_t *
perfmon_start (vlib_main_t *vm, perfmon_bundle_t *b)
{
@@ -238,20 +266,28 @@ perfmon_start (vlib_main_t *vm, perfmon_bundle_t *b)
}
if (b->active_type == PERFMON_BUNDLE_TYPE_NODE)
{
for (int i = 0; i < vec_len (pm->thread_runtimes); i++)
{
perfmon_thread_runtime_t *tr;
tr = vec_elt_at_index (pm->thread_runtimes, i);
vlib_node_function_t *funcs[PERFMON_OFFSET_TYPE_MAX];
#define _(type, pfunc) funcs[type] = pfunc;
for (int j = 0; j < b->n_events; j++)
{
tr->indexes[j] = perfmon_mmap_read_index (tr->mmap_pages[j]);
foreach_permon_offset_type
#undef _
ASSERT (funcs[b->offset_type]);
/* if a zero index is returned generate error */
if (!tr->indexes[j])
{
perfmon_reset (vm);
return clib_error_return (0, "invalid rdpmc index");
}
}
}
for (int i = 0; i < vlib_get_n_threads (); i++)
vlib_node_set_dispatch_wrapper (vlib_get_main_by_index (i),
funcs[b->offset_type]);
perfmon_dispatch_wrapper);
}
pm->sample_time = vlib_time_now (vm);
pm->is_running = 1;

20
src/plugins/perfmon/perfmon.h
View File

@@ -49,13 +49,6 @@ typedef enum
} perfmon_bundle_type_flag_t;
typedef enum
{
PERFMON_OFFSET_TYPE_MMAP,
PERFMON_OFFSET_TYPE_METRICS,
PERFMON_OFFSET_TYPE_MAX,
} perfmon_offset_type_t;
typedef struct
{
u32 type_from_instance : 1;
@@ -85,12 +78,7 @@ typedef struct
} perfmon_instance_type_t;
struct perfmon_source;
vlib_node_function_t perfmon_dispatch_wrapper_mmap;
vlib_node_function_t perfmon_dispatch_wrapper_metrics;
#define foreach_permon_offset_type \
_ (PERFMON_OFFSET_TYPE_MMAP, perfmon_dispatch_wrapper_mmap) \
_ (PERFMON_OFFSET_TYPE_METRICS, perfmon_dispatch_wrapper_metrics)
vlib_node_function_t perfmon_dispatch_wrapper;
typedef clib_error_t *(perfmon_source_init_fn_t) (vlib_main_t *vm,
struct perfmon_source *);
@@ -131,12 +119,10 @@ typedef struct perfmon_bundle
};
perfmon_bundle_type_t active_type;
perfmon_offset_type_t offset_type;
u32 events[PERF_MAX_EVENTS];
u32 n_events;
u32 metrics[PERF_MAX_EVENTS];
u32 n_metrics;
u16 preserve_samples;
perfmon_cpu_supports_t *cpu_supports;
u32 n_cpu_supports;
@@ -180,6 +166,8 @@ typedef struct
u16 n_nodes;
perfmon_node_stats_t *node_stats;
perfmon_bundle_t *bundle;
u32 indexes[PERF_MAX_EVENTS];
u16 preserve_samples;
struct perf_event_mmap_page *mmap_pages[PERF_MAX_EVENTS];
} perfmon_thread_runtime_t;