# Composable Kernel Build Time Analysis Report

**Generated:** {{ timestamp }}
**Target:** {{ target }}
**Granularity:** {{ granularity }}µs
**Files Analyzed:** {{ num_files }}

## Executive Summary

- **Wall Clock Time:** {{ build_time }} seconds
- **Trace Time:** {{ total_trace_time|us_to_s|round(1) }} seconds
- **Template Instantiation Time:** {{ total_template_time|us_to_s|round(1) }} seconds ({{ (100 * total_template_time / total_trace_time)|round(1) }}% of trace)
- **Total Events Captured:** {{ total_events|format_number }} (across {{ num_files }} file{{ 's' if num_files != 1 else '' }})
- **Total Template Instantiations:** {{ total_instantiations|format_number }}
- **Unique Template Families:** {{ unique_families }}

{% if num_files > 1 -%}
## Per-File Analysis

| File | Events | Template Time (ms) | % of Total |
|------|--------|-------------------|------------|
{% for file in file_stats[:20] -%}
| {{ file.name|truncate(50)|pad(50) }} | {{ "%7d"|format(file.events) }} | {{ "%17.2f"|format(file.template_time|us_to_ms) }} | {{ "%9.1f"|format(100 * file.template_time / total_template_time if total_template_time > 0 else 0) }}% |
{% endfor %}

{% endif -%}
## Compilation Phase Breakdown

| Phase | Time (ms) | Time (s) | % of Total |
|-------|-----------|----------|------------|
{% for phase, dur in phases[:20] -%}
| {{ phase|pad(40) }} | {{ "%9.2f"|format(dur|us_to_ms) }} | {{ "%8.2f"|format(dur|us_to_s) }} | {{ "%9.1f"|format(100 * dur / total_trace_time) }}% |
{% endfor %}

## Top 30 Most Expensive Individual Instantiations

{% if num_files > 1 -%}
| Rank | Template | Type | Time (ms) | File |
|------|----------|------|-----------|------|
{% for inst in top_individual[:30] -%}
| {{ "%4d"|format(loop.index) }} | {{ inst.detail|truncate(50) }} | {{ inst.inst_type|pad(5) }} | {{ "%9.2f"|format(inst.dur|us_to_ms) }} | {{ inst.file|truncate(20) }} |
{% endfor -%}
{% else -%}
| Rank | Template | Type | Time (ms) |
|------|----------|------|-----------|
{% for inst in top_individual[:30] -%}
| {{ "%4d"|format(loop.index) }} | {{ inst.detail|truncate(70) }} | {{ inst.inst_type|pad(5) }} | {{ "%9.2f"|format(inst.dur|us_to_ms) }} |
{% endfor -%}
{% endif %}

## Template Families by Total Time (Top 50)

| Rank | Template Family | Count | Total (ms) | Avg (ms) | % of Total |
|------|-----------------|-------|------------|----------|------------|
{% for name, stats in templates_by_time[:50] -%}
| {{ "%4d"|format(loop.index) }} | {{ name|truncate(43)|pad(43) }} | {{ "%5d"|format(stats.count) }} | {{ "%10.2f"|format(stats.total_dur|us_to_ms) }} | {{ "%8.2f"|format(stats.avg|us_to_ms) }} | {{ "%9.1f"|format(stats.pct) }}% |
{% endfor %}

## Template Families by Instantiation Count (Top 50)

| Rank | Template Family | Count | Total (ms) | Avg (ms) |
|------|-----------------|-------|------------|----------|
{% for name, stats in templates_by_count[:50] -%}
| {{ "%4d"|format(loop.index) }} | {{ name|truncate(43)|pad(43) }} | {{ "%5d"|format(stats.count) }} | {{ "%10.2f"|format(stats.total_dur|us_to_ms) }} | {{ "%8.2f"|format(stats.avg|us_to_ms) }} |
{% endfor %}

## Key Insights

### 1. Template Instantiation Impact
- Template instantiation accounts for {{ (100 * total_template_time / total_trace_time)|round(1) }}% of total trace time
{% if unique_families >= 10 -%}
- Top 10 template families account for {{ top10_pct|round(1) }}% of instantiation time
{% endif %}

### 2. Most Expensive Templates
{% if templates_by_time|length > 0 -%}
- **{{ templates_by_time[0][0] }}**: {{ templates_by_time[0][1].count|format_number }} instantiations, {{ (templates_by_time[0][1].total_dur|us_to_s)|round(2) }}s total
{% endif -%}
{% if templates_by_time|length > 1 -%}
- **{{ templates_by_time[1][0] }}**: {{ templates_by_time[1][1].count|format_number }} instantiations, {{ (templates_by_time[1][1].avg|us_to_ms)|round(2) }}ms average
{% endif %}

## Optimization Recommendations

### High-Impact Targets (by total time)
{% for name, stats in templates_by_time[:5] -%}
**{{ loop.index }}. {{ name }}** - {{ (stats.total_dur|us_to_s)|round(1) }}s total ({{ stats.pct|round(1) }}%)
   - {{ stats.count|format_number }} instantiations, {{ (stats.avg|us_to_ms)|round(2) }}ms average
   {% if stats.count > 100 -%}
   - Strategy: Extern templates - High instantiation count suggests repeated compilation
   {% elif stats.avg|us_to_ms > 50 -%}
   - Strategy: Template specialization - High individual cost suggests complexity
   {% else -%}
   - Strategy: Explicit instantiation - Pre-instantiate common configurations
   {% endif %}

{% endfor %}
### Frequently Instantiated (optimization candidates)
{% for name, stats in templates_by_count[:5] if stats.count > 100 -%}
**{{ name }}** - {{ stats.count|format_number }} times ({{ (stats.total_dur|us_to_s)|round(2) }}s total)
   - Consider: Precompiled headers or extern templates to avoid recompilation

{% endfor %}
### Most Expensive Individual Instantiations
{% for inst in top_individual[:3] -%}
**{{ loop.index }}. {{ inst.detail|truncate(60) }}** - {{ (inst.dur|us_to_ms)|round(1) }}ms
   - Strategy: Profile and simplify this specific instantiation

{% endfor %}

## Detailed Statistics

- **Total Unique Templates:** {{ unique_families }}
- **Total Instantiations:** {{ total_instantiations|format_number }}
{% if total_instantiations > 0 -%}
- **Average Instantiation Time:** {{ ((total_template_time // total_instantiations)|us_to_ms)|round(3) }}ms
{% endif -%}
{% if unique_families > 0 -%}
- **Median Template Family Count:** {{ median_count }}
{% endif %}

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*Report generated using Clang -ftime-trace with {{ granularity }}µs granularity*
*Analysis tool: ck-build-analysis*