ayourtch

GPU Kernel Profiling with ncu — A Practical Guide

Written: 2026-05-11 Audience: developer familiar with CUDA but new to hardware-counter profiling Based on: a real profiling session of a large language model inference engine on an NVIDIA GB10 (Grace Blackwell, sm_121, CUDA 13.0)

---

Background: what we were optimizing and why

ayourtch

# Define a shared memory zone to store rate limit state
limit_req_zone $binary_remote_addr zone=req_limit_per_ip:10m rate=10r/s;

# Define a map to store the last failed attempt timestamp
map $remote_addr $last_failed_time {
    volatile;
    default 0;
}

# Define a map to store the retry count

ayourtch

# coding=utf-8
# Copyright 2023 The HuggingFace Inc. team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software

ayourtch

use int_enum::IntEnum;
use std::convert::TryFrom;
use serde::{Deserialize, Serialize};
use serde_json::Result;
use bincode::Options;


#[repr(u32)]
#[derive(Clone, Copy, Debug, Eq, PartialEq, Serialize, Deserialize, IntEnum)]
enum DT {

ayourtch

DEB artifact versions, in DEB sort order applied, currently:


19.08.2-release              <--- in fdio/release
19.08.2-2~g220e40541~b2500       |
19.08.2-1~g99fa5f722~b2499       | <--- fdio/1908
19.08.1-release               <--- in fdio/release
19.08.1-402~g0830008b3~b2497     |
19.08.1-401~g8e4ed521a~b2496     |
...

ayourtch

#define _GNU_SOURCE
#include <stdio.h>
#include <string.h>
#include <stdlib.h>


 static int order(char c)
 {
    if (isdigit(c))
       return 0;

ayourtch

Patches that changed FEATURE.yaml definitions

| @c extras/deprecated/netmap/FEATURE.yaml || | 7db6ab03d | misc: deprecate netmap and ixge drivers |

diff --git a/extras/deprecated/netmap/FEATURE.yaml b/extras/deprecated/netmap/FEATURE.yaml
new file mode 100644
index 000000000..e23e5c243
--- /dev/null
+++ b/extras/deprecated/netmap/FEATURE.yaml

ayourtch

#ifndef INCLUDE_CUSTOM_CODEGEN
#define INCLUDE_CUSTOM_CODEGEN

// #define CAT(a, ...) CCG_PRIMITIVE_CAT(a, __VA_ARGS__)
#define CCG_PRIMITIVE_CAT(a, ...) a ## __VA_ARGS__

#define EXCEPTION_CHECK_N(x, n, ...) n
#define EXCEPTION_CHECK(...) EXCEPTION_CHECK_N(__VA_ARGS__, USUAL_HANDLING,)
#define DEFAULT_EXCEPTION SPECIAL_PROC(~)
#define SPECIAL_PROC(x) x, EXCEPTION_HANDLING,

ayourtch

/* run this through CPP to see what this is all about */
  
/* this would be a separate include file but for simplicity we leave it here */

#define CAT(a, ...) PRIMITIVE_CAT(a, __VA_ARGS__)
#define PRIMITIVE_CAT(a, ...) a ## __VA_ARGS__

#define EXCEPTION_CHECK_N(x, n, ...) n
#define EXCEPTION_CHECK(...) EXCEPTION_CHECK_N(__VA_ARGS__, USUAL_HANDLING,)
#define DEFAULT_EXCEPTION SPECIAL_PROC(~)

ayourtch

extern crate chrono;
extern crate diesel;

use super::flextimestamp::FlexTimestamp;
use super::flexuuid::FlexUuid;

use super::models;
use super::schema;
use diesel::pg::PgConnection;
use diesel::prelude::*;