Overview

API Introduction

The Trace module provides C++ APIs for collecting inference performance data for trace data monitoring.

For details about the functions and usage examples of the Trace APIs, see msServiceProfiler Trace Data Monitoring.

Header file: ${INSTALL_DIR}/include/Tracer.h

Library file: ${INSTALL_DIR}/lib64/libms_service_profiler.so

Replace $\{INSTALL\_DIR\} with the CANN software installation path. For example, if the installation is performed by the root user, the path is /usr/local/Ascend/cann.

Sample Code

The following code example illustrates key steps and is for reference only. Do not copy and compile it directly.

// Set global resource attributes.
if (msServiceProfiler::Tracer::IsEnable()) {
    msServiceProfiler::TraceContext::addResAttribute("service.name", "my-service");
    msServiceProfiler::TraceContext::addResAttribute("service.version", "1.0.0");
}
auto& ctx = msServiceProfiler::TraceContext::GetTraceCtx();
size_t indexHeader = ctx.ExtractAndAttach(traceParentHeader, b3Header);
size_t index = ctx.Attach(TraceId{1, 1}, SpanId{1}, true); // Spans are attached automatically. This function is generally not needed.
// Create a span.
auto span = msServiceProfiler::Tracer::StartSpanAsActive("MyOperation", "MyModule");
// Set attributes.
span.SetAttribute("key", "value")
    .SetStatus(true, "Operation completed successfully");
span.End();
ctx.Unattach(index);
ctx.Unattach(indexHeader);

API List

APIs are listed below.

Table 1 Trace APIs (C++)

API	Description
TraceContext	Trace context management class, which manages thread-level trace information.
GetTraceCtx	Obtains the trace context instance for the current thread.
addResAttribute	Adds resource attributes (global attributes).
ExtractAndAttach	Parses HTTP trace information and attaches it to the current context.
Attach	Attaches trace information to the current context.
Unattach	Detaches the trace context with a specified index.
GetCurrent	Obtains the current trace context.
Span Class	Span class, which represents a specific operation or request.
Span	Creates a span.
Activate	Activates the span and starts timing.
SetAttribute	Sets the span attribute.
SetStatus	Sets the span status.
End	Ends the span.
Tracer Class	Provides APIs for creating spans.
StartSpanAsActive	Creates and activates a span.
IsEnable	Checks whether the trace feature is enabled.