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fix: time unit not match in ThreadMetricUtil.cpp #5607

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merged 2 commits into from
Aug 11, 2022
Merged

fix: time unit not match in ThreadMetricUtil.cpp #5607

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0274346
fix again...
Lloyd-Pottiger Aug 11, 2022
27b6331
Merge branch 'master' into fix-bug
ti-chi-bot Aug 11, 2022
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18 changes: 9 additions & 9 deletions dbms/src/Common/ThreadMetricUtil.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -12,24 +12,24 @@
// See the License for the specific language governing permissions and
// limitations under the License.

#include <Common/Stopwatch.h>
#include <Common/ThreadMetricUtil.h>
#include <Common/TiFlashMetrics.h>
#include <common/types.h>

std::atomic<UInt64> last_max_thds_metric_reset_ts{0};
const std::chrono::duration<UInt64> max_thds_metric_reset_interval{60}; // 60s
using Clock = std::chrono::steady_clock;
using TimePoint = Clock::time_point;
std::atomic<TimePoint> last_max_thds_metric_reset_ts{};
const std::chrono::seconds max_thds_metric_reset_interval{60}; // 60s

namespace DB
{
bool tryToResetMaxThreadsMetrics()
{
using nanoseconds = std::chrono::duration<UInt64, std::nano>;
UInt64 last_max_thds_metric_reset_ts_tmp = last_max_thds_metric_reset_ts.load(std::memory_order_relaxed);
UInt64 now_ts = clock_gettime_ns_adjusted(last_max_thds_metric_reset_ts_tmp, CLOCK_MONOTONIC);
if (nanoseconds(now_ts) > nanoseconds(last_max_thds_metric_reset_ts_tmp) + max_thds_metric_reset_interval)
auto last_max_thds_metric_reset_ts_tmp = last_max_thds_metric_reset_ts.load(std::memory_order_relaxed);
Comment on lines -29 to +28
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@bestwoody bestwoody Aug 11, 2022 •
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is overhead of new one the same as clock_monotonic？

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actually, a little bit slower……

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then I think that will be bad，why bother changing into a slower one...

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Class std::chrono::steady_clock represents a monotonic clock. The time points of this clock cannot decrease as physical time moves forward and the time between ticks of this clock is constant. This clock is not related to wall clock time (for example, it can be time since last reboot), and is most suitable for measuring intervals.

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it is better to use std::chrono::steady_clock to measure intervals.

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Guess std::chrono::steady_clock actually calls clock_gettime(MONOTONIC). you can try to confirm it.

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libstdc++: https://github.com/gcc-mirror/gcc/blob/master/libstdc%2B%2B-v3/src/c%2B%2B11/chrono.cc#L87

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libc++: https://github.com/llvm-mirror/libcxx/blob/master/src/chrono.cpp#L220

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please do things right.

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lgtm

auto now = std::max(Clock::now(), last_max_thds_metric_reset_ts_tmp);
if (now > last_max_thds_metric_reset_ts_tmp + max_thds_metric_reset_interval)
{
last_max_thds_metric_reset_ts.store(now_ts, std::memory_order_relaxed);
last_max_thds_metric_reset_ts.store(now, std::memory_order_relaxed);
GET_METRIC(tiflash_thread_count, type_max_threads_of_dispatch_mpp).Set(GET_METRIC(tiflash_thread_count, type_active_threads_of_dispatch_mpp).Value());
GET_METRIC(tiflash_thread_count, type_max_threads_of_establish_mpp).Set(GET_METRIC(tiflash_thread_count, type_active_threads_of_establish_mpp).Value());
GET_METRIC(tiflash_thread_count, type_max_threads_of_raw).Set(GET_METRIC(tiflash_thread_count, type_total_threads_of_raw).Value());
Expand All @@ -39,4 +39,4 @@ bool tryToResetMaxThreadsMetrics()
}
return false;
}
} // namespace DB
} // namespace DB