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intel/ds: drop timestamp correlation code

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Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Antonio Caggiano <antonio.caggiano@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13831>
This commit is contained in:
Lionel Landwerlin 2021-11-08 00:09:08 +02:00 • committed by Marge Bot
parent 21a1c6995c
commit 4ef6698a26
2 changed files with 88 additions and 159 deletions
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202
src/intel/ds/intel_pps_driver.cc
View file

@ -37,6 +37,45 @@ uint64_t IntelDriver::get_min_sampling_period_ns()
return (2.f * perf->devinfo.timestamp_frequency) / 1000000000ull; return (2.f * perf->devinfo.timestamp_frequency) / 1000000000ull;
} }
uint64_t scale_gpu_timestamp(uint64_t ts, uint64_t timestamp_frequency)
{
// Try to avoid going over the 64bits when doing the scaling
uint64_t lower_ts = ts >> 6;
uint64_t scaled_ts = lower_ts * 1000000000ull / timestamp_frequency;
scaled_ts <<= 6;
scaled_ts += (ts & 0x3f) * 1000000000ull / timestamp_frequency;
return scaled_ts;
}
uint64_t read_gpu_timestamp(int drm_fd)
{
drm_i915_reg_read reg_read = {};
const uint64_t render_ring_timestamp = 0x2358;
reg_read.offset = render_ring_timestamp | I915_REG_READ_8B_WA;
if (perf_ioctl(drm_fd, DRM_IOCTL_I915_REG_READ, &reg_read) < 0) {
PPS_LOG_ERROR("Unable to read GPU clock");
return 0;
}
return reg_read.val;
}
IntelDriver::IntelDriver()
{
/* Note: clock_id's below 128 are reserved.. for custom clock sources,
* using the hash of a namespaced string is the recommended approach.
* See: https://perfetto.dev/docs/concepts/clock-sync
*/
this->clock_id =
_mesa_hash_string("org.freedesktop.mesa.intel") | 0x80000000;
}
IntelDriver::~IntelDriver()
{
}
void IntelDriver::enable_counter(uint32_t counter_id) void IntelDriver::enable_counter(uint32_t counter_id)
{ {
auto &counter = counters[counter_id]; auto &counter = counters[counter_id];
@ -75,71 +114,6 @@ void IntelDriver::enable_all_counters()
} }
} }
static uint64_t timespec_diff(timespec *begin, timespec *end)
{
return 1000000000ull * (end->tv_sec - begin->tv_sec) + end->tv_nsec - begin->tv_nsec;
}
/// @brief This function tries to correlate CPU time with GPU time
std::optional<TimestampCorrelation> IntelDriver::query_correlation_timestamps() const
{
TimestampCorrelation corr = {};
clock_t correlation_clock_id = CLOCK_BOOTTIME;
drm_i915_reg_read reg_read = {};
const uint64_t render_ring_timestamp = 0x2358;
reg_read.offset = render_ring_timestamp | I915_REG_READ_8B_WA;
constexpr size_t attempt_count = 3;
struct {
timespec cpu_ts_begin;
timespec cpu_ts_end;
uint64_t gpu_ts;
} attempts[attempt_count] = {};
uint32_t best = 0;
// Gather 3 correlations
for (uint32_t i = 0; i < attempt_count; i++) {
clock_gettime(correlation_clock_id, &attempts[i].cpu_ts_begin);
if (perf_ioctl(drm_device.fd, DRM_IOCTL_I915_REG_READ, &reg_read) < 0) {
return std::nullopt;
}
clock_gettime(correlation_clock_id, &attempts[i].cpu_ts_end);
attempts[i].gpu_ts = reg_read.val;
}
// Now select the best
for (uint32_t i = 1; i < attempt_count; i++) {
if (timespec_diff(&attempts[i].cpu_ts_begin, &attempts[i].cpu_ts_end) <
timespec_diff(&attempts[best].cpu_ts_begin, &attempts[best].cpu_ts_end)) {
best = i;
}
}
corr.cpu_timestamp =
(attempts[best].cpu_ts_begin.tv_sec * 1000000000ull + attempts[best].cpu_ts_begin.tv_nsec) +
timespec_diff(&attempts[best].cpu_ts_begin, &attempts[best].cpu_ts_end) / 2;
corr.gpu_timestamp = attempts[best].gpu_ts;
return corr;
}
void IntelDriver::get_new_correlation()
{
// Rotate left correlations by one position so to make space at the end
std::rotate(correlations.begin(), correlations.begin() + 1, correlations.end());
// Then we overwrite the last correlation with a new one
if (auto corr = query_correlation_timestamps()) {
correlations.back() = *corr;
} else {
PPS_LOG_FATAL("Failed to get correlation timestamps");
}
}
bool IntelDriver::init_perfcnt() bool IntelDriver::init_perfcnt()
{ {
assert(!perf && "Intel perf should not be initialized at this point"); assert(!perf && "Intel perf should not be initialized at this point");
@ -201,41 +175,11 @@ void IntelDriver::enable_perfcnt(uint64_t sampling_period_ns)
{ {
this->sampling_period_ns = sampling_period_ns; this->sampling_period_ns = sampling_period_ns;
// Fill correlations with an initial one
if (auto corr = query_correlation_timestamps()) {
correlations.fill(*corr);
} else {
PPS_LOG_FATAL("Failed to get correlation timestamps");
}
if (!perf->open(sampling_period_ns)) { if (!perf->open(sampling_period_ns)) {
PPS_LOG_FATAL("Failed to open intel perf"); PPS_LOG_FATAL("Failed to open intel perf");
} }
} }
/// @brief Transforms the GPU timestop into a CPU timestamp equivalent
uint64_t IntelDriver::correlate_gpu_timestamp(const uint32_t gpu_ts)
{
auto &corr_a = correlations[0];
auto &corr_b = correlations[correlations.size() - 1];
// A correlation timestamp has 36 bits, so get the first 32 to make it work with gpu_ts
uint64_t mask = 0xffffffff;
uint32_t corr_a_gpu_ts = corr_a.gpu_timestamp & mask;
uint32_t corr_b_gpu_ts = corr_b.gpu_timestamp & mask;
// Make sure it is within the interval [a,b)
assert(gpu_ts >= corr_a_gpu_ts && "GPU TS < Corr a");
assert(gpu_ts < corr_b_gpu_ts && "GPU TS >= Corr b");
uint32_t gpu_delta = gpu_ts - corr_a_gpu_ts;
// Factor to convert gpu time to cpu time
double gpu_to_cpu = (corr_b.cpu_timestamp - corr_a.cpu_timestamp) /
double(corr_b.gpu_timestamp - corr_a.gpu_timestamp);
uint64_t cpu_delta = gpu_delta * gpu_to_cpu;
return corr_a.cpu_timestamp + cpu_delta;
}
void IntelDriver::disable_perfcnt() void IntelDriver::disable_perfcnt()
{ {
perf = nullptr; perf = nullptr;
@ -244,12 +188,6 @@ void IntelDriver::disable_perfcnt()
enabled_counters.clear(); enabled_counters.clear();
} }
struct Report {
uint32_t version;
uint32_t timestamp;
uint32_t id;
};
/// @brief Some perf record durations can be really short /// @brief Some perf record durations can be really short
/// @return True if the duration is at least close to the sampling period /// @return True if the duration is at least close to the sampling period
static bool close_enough(uint64_t duration, uint64_t sampling_period) static bool close_enough(uint64_t duration, uint64_t sampling_period)
@ -265,12 +203,12 @@ std::vector<PerfRecord> IntelDriver::parse_perf_records(const std::vector<uint8_
records.reserve(128); records.reserve(128);
PerfRecord record; PerfRecord record;
record.reserve(512); record.data.reserve(512);
const uint8_t *iter = data.data(); const uint8_t *iter = data.data();
const uint8_t *end = iter + byte_count; const uint8_t *end = iter + byte_count;
uint64_t prev_cpu_timestamp = last_cpu_timestamp; uint64_t prev_gpu_timestamp = last_gpu_timestamp;
while (iter < end) { while (iter < end) {
// Iterate a record at a time // Iterate a record at a time
@ -278,18 +216,32 @@ std::vector<PerfRecord> IntelDriver::parse_perf_records(const std::vector<uint8_
if (header->type == DRM_I915_PERF_RECORD_SAMPLE) { if (header->type == DRM_I915_PERF_RECORD_SAMPLE) {
// Report is next to the header // Report is next to the header
auto report = reinterpret_cast<const Report *>(header + 1); const uint32_t *report = reinterpret_cast<const uint32_t *>(header + 1);
auto cpu_timestamp = correlate_gpu_timestamp(report->timestamp); uint64_t gpu_timestamp_ldw =
auto duration = cpu_timestamp - prev_cpu_timestamp; intel_perf_report_timestamp(&perf->query.value(), report);
/* Our HW only provides us with the lower 32 bits of the 36bits
* timestamp counter value. If we haven't captured the top bits yet,
* do it now. If we see a roll over the lower 32bits capture it
* again.
*/
if (gpu_timestamp_udw == 0 || (gpu_timestamp_udw + gpu_timestamp_ldw) < last_gpu_timestamp)
gpu_timestamp_udw = read_gpu_timestamp(drm_device.fd) & 0xffffffff00000000;
uint64_t gpu_timestamp = gpu_timestamp_udw + gpu_timestamp_ldw;
auto duration = scale_gpu_timestamp(gpu_timestamp - prev_gpu_timestamp,
perf->devinfo.timestamp_frequency);
// Skip perf-records that are too short by checking // Skip perf-records that are too short by checking
// the distance between last report and this one // the distance between last report and this one
if (close_enough(duration, sampling_period_ns)) { if (close_enough(duration, sampling_period_ns)) {
prev_cpu_timestamp = cpu_timestamp; prev_gpu_timestamp = gpu_timestamp;
// Add the new record to the list // Add the new record to the list
record.resize(header->size); // Possibly 264? record.timestamp = gpu_timestamp;
memcpy(record.data(), iter, header->size); record.data.resize(header->size); // Possibly 264?
memcpy(record.data.data(), iter, header->size);
records.emplace_back(record); records.emplace_back(record);
} }
} }
@ -329,8 +281,6 @@ bool IntelDriver::dump_perfcnt()
read_data_from_metric_set(); read_data_from_metric_set();
get_new_correlation();
auto new_records = parse_perf_records(metric_buffer, total_bytes_read); auto new_records = parse_perf_records(metric_buffer, total_bytes_read);
if (new_records.empty()) { if (new_records.empty()) {
PPS_LOG("No new records"); PPS_LOG("No new records");
@ -353,7 +303,7 @@ bool IntelDriver::dump_perfcnt()
return true; return true;
} }
uint32_t IntelDriver::gpu_next() uint64_t IntelDriver::gpu_next()
{ {
if (records.size() < 2) { if (records.size() < 2) {
// Not enough records to accumulate // Not enough records to accumulate
@ -361,8 +311,8 @@ uint32_t IntelDriver::gpu_next()
} }
// Get first and second // Get first and second
auto record_a = reinterpret_cast<const drm_i915_perf_record_header *>(records[0].data()); auto record_a = reinterpret_cast<const drm_i915_perf_record_header *>(records[0].data.data());
auto record_b = reinterpret_cast<const drm_i915_perf_record_header *>(records[1].data()); auto record_b = reinterpret_cast<const drm_i915_perf_record_header *>(records[1].data.data());
intel_perf_query_result_accumulate_fields(&result, intel_perf_query_result_accumulate_fields(&result,
&perf->query.value(), &perf->query.value(),
@ -372,42 +322,30 @@ uint32_t IntelDriver::gpu_next()
false /* no_oa_accumulate */); false /* no_oa_accumulate */);
// Get last timestamp // Get last timestamp
auto report_b = reinterpret_cast<const Report *>(record_b + 1); auto gpu_timestamp = records[1].timestamp;
auto gpu_timestamp = report_b->timestamp;
// Consume first record // Consume first record
records.erase(std::begin(records), std::begin(records) + 1); records.erase(std::begin(records), std::begin(records) + 1);
return gpu_timestamp; return scale_gpu_timestamp(gpu_timestamp, perf->devinfo.timestamp_frequency);
}
uint64_t IntelDriver::cpu_next()
{
if (auto gpu_timestamp = gpu_next()) {
auto cpu_timestamp = correlate_gpu_timestamp(gpu_timestamp);
last_cpu_timestamp = cpu_timestamp;
return cpu_timestamp;
}
return 0;
} }
uint64_t IntelDriver::next() uint64_t IntelDriver::next()
{ {
// Reset accumulation // Reset accumulation
intel_perf_query_result_clear(&result); intel_perf_query_result_clear(&result);
return cpu_next(); return gpu_next();
} }
uint32_t IntelDriver::gpu_clock_id() const uint32_t IntelDriver::gpu_clock_id() const
{ {
return perfetto::protos::pbzero::BUILTIN_CLOCK_BOOTTIME; return this->clock_id;
} }
uint64_t IntelDriver::gpu_timestamp() const uint64_t IntelDriver::gpu_timestamp() const
{ {
return perfetto::base::GetBootTimeNs().count(); return scale_gpu_timestamp(read_gpu_timestamp(drm_device.fd),
perf->devinfo.timestamp_frequency);
} }
} // namespace pps } // namespace pps

45
src/intel/ds/intel_pps_driver.h
View file

@ -13,17 +13,15 @@
namespace pps namespace pps
{ {
/// Timestamp correlation between CPU/GPU.
struct TimestampCorrelation {
/// In CLOCK_MONOTONIC
uint64_t cpu_timestamp;
/// Engine timestamp associated with the OA unit
uint64_t gpu_timestamp;
};
/// @brief Variable length sequence of bytes generated by Intel Obstervation Architecture (OA) /// @brief Variable length sequence of bytes generated by Intel Obstervation Architecture (OA)
using PerfRecord = std::vector<uint8_t>; struct PerfRecord {
/// Timestamp in the GPU clock domain
uint64_t timestamp;
/// drm_i915_perf_record_header + report data
std::vector<uint8_t> data;
};
/// @brief PPS Driver implementation for Intel graphics devices. /// @brief PPS Driver implementation for Intel graphics devices.
/// When sampling it may collect multiple perf-records at once. Each perf-record holds multiple /// When sampling it may collect multiple perf-records at once. Each perf-record holds multiple
@ -34,14 +32,8 @@ using PerfRecord = std::vector<uint8_t>;
class IntelDriver : public Driver class IntelDriver : public Driver
{ {
public: public:
std::optional<TimestampCorrelation> query_correlation_timestamps() const; IntelDriver();
void get_new_correlation(); ~IntelDriver();
/// @brief OA reports only have the lower 32 bits of the timestamp
/// register, while correlation data has the whole 36 bits.
/// @param gpu_ts a 32 bit OA report GPU timestamp
/// @return The CPU timestamp relative to the argument
uint64_t correlate_gpu_timestamp(uint32_t gpu_ts);
uint64_t get_min_sampling_period_ns() override; uint64_t get_min_sampling_period_ns() override;
bool init_perfcnt() override; bool init_perfcnt() override;
@ -57,12 +49,7 @@ class IntelDriver : public Driver
private: private:
/// @brief Requests the next perf sample /// @brief Requests the next perf sample
/// @return The sample GPU timestamp /// @return The sample GPU timestamp
uint32_t gpu_next(); uint64_t gpu_next();
/// @brief Requests the next perf sample accumulating those which
/// which duration is shorter than the requested sampling period
/// @return The sample CPU timestamp
uint64_t cpu_next();
/// @param data Buffer of bytes to parse /// @param data Buffer of bytes to parse
/// @param byte_count Number of bytes to parse /// @param byte_count Number of bytes to parse
@ -75,11 +62,12 @@ class IntelDriver : public Driver
/// Sampling period in nanoseconds requested by the datasource /// Sampling period in nanoseconds requested by the datasource
uint64_t sampling_period_ns = 0; uint64_t sampling_period_ns = 0;
/// Keep track of the timestamp of the last sample generated /// Last upper 32bits of the GPU timestamp in the parsed reports
uint64_t last_cpu_timestamp = 0; uint64_t gpu_timestamp_udw = 0;
/// This is used to correlate CPU and GPU timestamps /// Keep track of the timestamp of the last sample generated (upper & lower
std::array<TimestampCorrelation, 64> correlations; /// 32bits)
uint64_t last_gpu_timestamp = 0;
/// Data buffer used to store data read from the metric set /// Data buffer used to store data read from the metric set
std::vector<uint8_t> metric_buffer = std::vector<uint8_t>(1024, 0); std::vector<uint8_t> metric_buffer = std::vector<uint8_t>(1024, 0);
@ -94,6 +82,9 @@ class IntelDriver : public Driver
// Accumulations are stored here // Accumulations are stored here
struct intel_perf_query_result result = {}; struct intel_perf_query_result result = {};
// Gpu clock ID used to correlate GPU/CPU timestamps
uint32_t clock_id = 0;
}; };
} // namespace pps } // namespace pps