conproxy 0.2.1

Cache proxy server for heterogeneous RAG/vector search backends with cascade, scope, and MCP
Documentation 
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#!/usr/bin/env bpftrace
//
// lock_profile.bt — Lock contention profiling for conpack proxy.
//
// Traces futex(FUTEX_WAIT) and futex(FUTEX_WAKE) syscalls for the target PID.
// Shows which locks are contended and for how long.
//
// DashMap shards, parking_lot Mutex/RwLock, and Semaphore-based connection
// pools all ultimately use futex. High wait counts or long wait times
// indicate lock contention under load.
//
// Usage: sudo bpftrace -p <PID> lock_profile.bt <PID>
//

config = { max_map_keys = 16384 }

// FUTEX_WAIT = 0, FUTEX_WAKE = 1 (see linux/futex.h)

tracepoint:syscalls:sys_enter_futex / pid == $1 && (args.op & 0xf) == 0 /
{
    @futex_wait_start[tid] = nsecs;
    @futex_wait_count++;
    @futex_wait_by_stack[ustack(8)]++;
}

tracepoint:syscalls:sys_exit_futex / pid == $1 && @futex_wait_start[tid] /
{
    $lat = (nsecs - @futex_wait_start[tid]) / 1000;  // microseconds
    @futex_wait_latency_us = hist($lat);
    @futex_total_wait_us += $lat;
    @futex_wait_lat_by_stack[ustack(8)] += $lat;
    delete(@futex_wait_start[tid]);
}

tracepoint:syscalls:sys_enter_futex / pid == $1 && (args.op & 0xf) == 1 /
{
    @futex_wake_count++;
}

END
{
    printf("\n========================================\n");
    printf("CONPACK LOCK CONTENTION PROFILE SUMMARY\n");
    printf("========================================\n\n");

    printf("--- Totals ---\n");
    printf("futex_wait count:  %lld\n", @futex_wait_count);
    printf("futex_wake count:  %lld\n", @futex_wake_count);
    printf("total wait us:     %lld\n", @futex_total_wait_us);
    if (@futex_wait_count > 0) {
        printf("avg wait us:       %lld\n", @futex_total_wait_us / @futex_wait_count);
    }
    printf("\n");

    printf("--- Wait Latency Distribution (us) ---\n");
    print(@futex_wait_latency_us);
    printf("\n");

    printf("--- Top 15 Contended Lock Sites (by count) ---\n");
    print(@futex_wait_by_stack, 15);
    printf("\n");

    printf("--- Top 15 Contended Lock Sites (by total wait time) ---\n");
    print(@futex_wait_lat_by_stack, 15);
    printf("\n");

    // Clean up maps
    clear(@futex_wait_start);
    clear(@futex_wait_count);
    clear(@futex_wake_count);
    clear(@futex_total_wait_us);
    clear(@futex_wait_latency_us);
    clear(@futex_wait_by_stack);
    clear(@futex_wait_lat_by_stack);
}