From bc5c1c077cc5303d52351ce9df75a8d3914c1127 Mon Sep 17 00:00:00 2001
From: TYLER CARAZA-HARTER <tharter@cs544-tharter.cs.wisc.edu>
Date: Mon, 17 Feb 2025 12:14:19 -0600
Subject: [PATCH] lock demos
---
lec/11-threads/code/lec1b.ipynb | 284 ++++++++++++++++++++++++++++++++
lec/11-threads/code/lec2b.ipynb | 269 ++++++++++++++++++++++++++++++
2 files changed, 553 insertions(+)
create mode 100644 lec/11-threads/code/lec1b.ipynb
create mode 100644 lec/11-threads/code/lec2b.ipynb
diff --git a/lec/11-threads/code/lec1b.ipynb b/lec/11-threads/code/lec1b.ipynb
new file mode 100644
index 0000000..be93845
--- /dev/null
+++ b/lec/11-threads/code/lec1b.ipynb
@@ -0,0 +1,284 @@
+{
+ "cells": [
+ {
+ "cell_type": "code",
+ "execution_count": 1,
+ "id": "3b8d1ed9-9568-473e-bfa2-3b08f9e4587f",
+ "metadata": {},
+ "outputs": [],
+ "source": [
+ "import threading\n",
+ "import time"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 2,
+ "id": "da885575-cedf-4bb4-8bbd-44400974d3f8",
+ "metadata": {},
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ " 0 RESUME 0\n",
+ "\n",
+ " 1 LOAD_NAME 0 (total)\n",
+ " LOAD_CONST 0 (1)\n",
+ " BINARY_OP 13 (+=)\n",
+ " STORE_NAME 0 (total)\n",
+ " RETURN_CONST 1 (None)\n"
+ ]
+ }
+ ],
+ "source": [
+ "import dis\n",
+ "dis.dis(\"total += 1\")"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 3,
+ "id": "ceeb7904-ff2c-424c-bf7c-724d1b285e3b",
+ "metadata": {},
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "CPU times: user 133 ms, sys: 144 μs, total: 133 ms\n",
+ "Wall time: 129 ms\n"
+ ]
+ },
+ {
+ "data": {
+ "text/plain": [
+ "2000000"
+ ]
+ },
+ "execution_count": 3,
+ "metadata": {},
+ "output_type": "execute_result"
+ }
+ ],
+ "source": [
+ "%%time\n",
+ "# 133 ms with no locks\n",
+ "# 348 ms with locks (fine grained)\n",
+ "# 124 ms with locks (coarse grained)\n",
+ "\n",
+ "lock = threading.Lock() # this protects the \"total\" variable\n",
+ "total = 0\n",
+ "\n",
+ "def task(count):\n",
+ " global total\n",
+ " lock.acquire()\n",
+ " for i in range(count):\n",
+ " total += 1\n",
+ " lock.release()\n",
+ "\n",
+ "t1 = threading.Thread(target=task, args=[1_000_000])\n",
+ "t1.start()\n",
+ "\n",
+ "t2 = threading.Thread(target=task, args=[1_000_000])\n",
+ "t2.start()\n",
+ "\n",
+ "t1.join()\n",
+ "t2.join()\n",
+ "\n",
+ "total"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 3,
+ "id": "042356c8-7d34-4fa5-bef1-0c43e829fc13",
+ "metadata": {},
+ "outputs": [],
+ "source": [
+ "import threading\n",
+ "\n",
+ "bank_accounts = {\"x\": 25, \"y\": 100, \"z\": 200} # in dollars\n",
+ "lock = threading.Lock() # protects bank_accounts\n",
+ "\n",
+ "def transfer(src, dst, amount):\n",
+ " with lock: # automatically acquire now, and release after the with statement\n",
+ " success = False\n",
+ " if bank_accounts[src] >= amount:\n",
+ " bank_accounts[src] -= amount\n",
+ " bank_accounts[dst] += amount\n",
+ " success = True\n",
+ " print(\"transferred\" if success else \"denied\")\n",
+ " print(\"locked inside with?\", lock.locked())\n",
+ " print(\"locked after with?\", lock.locked())"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 4,
+ "id": "1878620a-553b-4f25-9606-1e2605b318ac",
+ "metadata": {},
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "transferred\n",
+ "locked inside with? True\n",
+ "locked after with? False\n"
+ ]
+ }
+ ],
+ "source": [
+ "transfer(\"x\", \"y\", 20)"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 5,
+ "id": "8901ec24-7471-40e1-8182-585d3cc760c7",
+ "metadata": {},
+ "outputs": [
+ {
+ "data": {
+ "text/plain": [
+ "{'x': 5, 'y': 120, 'z': 200}"
+ ]
+ },
+ "execution_count": 5,
+ "metadata": {},
+ "output_type": "execute_result"
+ }
+ ],
+ "source": [
+ "bank_accounts"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 6,
+ "id": "9cee2370-0f3d-4ac0-930a-c59f9f0d7f1b",
+ "metadata": {},
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "denied\n",
+ "locked inside with? True\n",
+ "locked after with? False\n"
+ ]
+ }
+ ],
+ "source": [
+ "transfer(\"x\", \"z\", 10)"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 7,
+ "id": "3a583c7c-57a3-4f42-8301-8ce601a2249e",
+ "metadata": {},
+ "outputs": [
+ {
+ "data": {
+ "text/plain": [
+ "{'x': 5, 'y': 120, 'z': 200}"
+ ]
+ },
+ "execution_count": 7,
+ "metadata": {},
+ "output_type": "execute_result"
+ }
+ ],
+ "source": [
+ "bank_accounts"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 8,
+ "id": "3346b86d-5f80-4007-8879-b452c4826c50",
+ "metadata": {},
+ "outputs": [
+ {
+ "ename": "KeyError",
+ "evalue": "'w'",
+ "output_type": "error",
+ "traceback": [
+ "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+ "\u001b[0;31mKeyError\u001b[0m Traceback (most recent call last)",
+ "Cell \u001b[0;32mIn[8], line 1\u001b[0m\n\u001b[0;32m----> 1\u001b[0m \u001b[43mtransfer\u001b[49m\u001b[43m(\u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mw\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mz\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;241;43m10\u001b[39;49m\u001b[43m)\u001b[49m\n",
+ "Cell \u001b[0;32mIn[3], line 9\u001b[0m, in \u001b[0;36mtransfer\u001b[0;34m(src, dst, amount)\u001b[0m\n\u001b[1;32m 7\u001b[0m \u001b[38;5;28;01mwith\u001b[39;00m lock:\n\u001b[1;32m 8\u001b[0m success \u001b[38;5;241m=\u001b[39m \u001b[38;5;28;01mFalse\u001b[39;00m\n\u001b[0;32m----> 9\u001b[0m \u001b[38;5;28;01mif\u001b[39;00m \u001b[43mbank_accounts\u001b[49m\u001b[43m[\u001b[49m\u001b[43msrc\u001b[49m\u001b[43m]\u001b[49m \u001b[38;5;241m>\u001b[39m\u001b[38;5;241m=\u001b[39m amount:\n\u001b[1;32m 10\u001b[0m bank_accounts[src] \u001b[38;5;241m-\u001b[39m\u001b[38;5;241m=\u001b[39m amount\n\u001b[1;32m 11\u001b[0m bank_accounts[dst] \u001b[38;5;241m+\u001b[39m\u001b[38;5;241m=\u001b[39m amount\n",
+ "\u001b[0;31mKeyError\u001b[0m: 'w'"
+ ]
+ }
+ ],
+ "source": [
+ "transfer(\"w\", \"z\", 10)"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 9,
+ "id": "02262baa-6f4f-455e-b913-accfa894cc18",
+ "metadata": {},
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "transferred\n",
+ "locked inside with? True\n",
+ "locked after with? False\n"
+ ]
+ }
+ ],
+ "source": [
+ "transfer(\"z\", \"x\", 3)"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 10,
+ "id": "1b338a2c-1274-41e8-9179-89b797e4ec2f",
+ "metadata": {},
+ "outputs": [
+ {
+ "data": {
+ "text/plain": [
+ "{'x': 8, 'y': 120, 'z': 197}"
+ ]
+ },
+ "execution_count": 10,
+ "metadata": {},
+ "output_type": "execute_result"
+ }
+ ],
+ "source": [
+ "bank_accounts"
+ ]
+ }
+ ],
+ "metadata": {
+ "kernelspec": {
+ "display_name": "Python 3.13-nogil",
+ "language": "python",
+ "name": "python3.13-nogil"
+ },
+ "language_info": {
+ "codemirror_mode": {
+ "name": "ipython",
+ "version": 3
+ },
+ "file_extension": ".py",
+ "mimetype": "text/x-python",
+ "name": "python",
+ "nbconvert_exporter": "python",
+ "pygments_lexer": "ipython3",
+ "version": "3.13.2"
+ }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}
diff --git a/lec/11-threads/code/lec2b.ipynb b/lec/11-threads/code/lec2b.ipynb
new file mode 100644
index 0000000..1bb0117
--- /dev/null
+++ b/lec/11-threads/code/lec2b.ipynb
@@ -0,0 +1,269 @@
+{
+ "cells": [
+ {
+ "cell_type": "code",
+ "execution_count": 1,
+ "id": "de014d74-4685-4f16-85fd-f571fd5a91db",
+ "metadata": {},
+ "outputs": [],
+ "source": [
+ "import threading"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 2,
+ "id": "82b2f08c-1a13-4a0f-9546-e5d624dbee5b",
+ "metadata": {},
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ " 0 RESUME 0\n",
+ "\n",
+ " 1 LOAD_NAME 0 (total)\n",
+ " LOAD_CONST 0 (1)\n",
+ " BINARY_OP 13 (+=)\n",
+ " STORE_NAME 0 (total)\n",
+ " RETURN_CONST 1 (None)\n"
+ ]
+ }
+ ],
+ "source": [
+ "import dis\n",
+ "dis.dis(\"total += 1\")"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 3,
+ "id": "ae617ed8-dd51-4154-ad83-308df527d1f1",
+ "metadata": {},
+ "outputs": [],
+ "source": [
+ "import threading"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 4,
+ "id": "b735264e-f27a-4d27-ba5f-4d6a1f53543e",
+ "metadata": {},
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "CPU times: user 151 ms, sys: 0 ns, total: 151 ms\n",
+ "Wall time: 148 ms\n"
+ ]
+ },
+ {
+ "data": {
+ "text/plain": [
+ "2000000"
+ ]
+ },
+ "execution_count": 4,
+ "metadata": {},
+ "output_type": "execute_result"
+ }
+ ],
+ "source": [
+ "%%time\n",
+ "# 141 ms (no locks)\n",
+ "# 340 ms (fine-grained locking)\n",
+ "# 122 ms (coarse-grained locking)\n",
+ "\n",
+ "lock = threading.Lock() # this protects total\n",
+ "total = 0\n",
+ "\n",
+ "def task(count):\n",
+ " global total\n",
+ " lock.acquire()\n",
+ " for i in range(count):\n",
+ " total += 1\n",
+ " lock.release()\n",
+ "\n",
+ "t1 = threading.Thread(target=task, args=[1_000_000])\n",
+ "t1.start()\n",
+ "t2 = threading.Thread(target=task, args=[1_000_000])\n",
+ "t2.start()\n",
+ "\n",
+ "t1.join()\n",
+ "t2.join()\n",
+ "\n",
+ "total"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 5,
+ "id": "7cf83d46-b7db-4ab6-b0bb-4b35fecba5b2",
+ "metadata": {},
+ "outputs": [],
+ "source": [
+ "bank_accounts = {\"x\": 25, \"y\": 100, \"z\": 200} # in dollars\n",
+ "lock = threading.Lock() # protects bank_accounts\n",
+ "\n",
+ "def transfer(src, dst, amount):\n",
+ " with lock: # automatically acquire now, automatically release after the with\n",
+ " success = False\n",
+ " if bank_accounts[src] >= amount:\n",
+ " bank_accounts[src] -= amount\n",
+ " bank_accounts[dst] += amount\n",
+ " success = True\n",
+ " print(\"transferred\" if success else \"denied\")\n",
+ " print(\"is it locked inside the with?\", lock.locked())\n",
+ " print(\"is it locked after the with?\", lock.locked())"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 6,
+ "id": "c9f19a3d-172f-4103-b631-11b42a8dc94c",
+ "metadata": {},
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "transferred\n",
+ "is it locked inside the with? True\n",
+ "is it locked after the with? False\n"
+ ]
+ },
+ {
+ "data": {
+ "text/plain": [
+ "{'x': 5, 'y': 120, 'z': 200}"
+ ]
+ },
+ "execution_count": 6,
+ "metadata": {},
+ "output_type": "execute_result"
+ }
+ ],
+ "source": [
+ "transfer(\"x\", \"y\", 20)\n",
+ "bank_accounts"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 7,
+ "id": "bdd94c73-dd01-4b9e-aecc-70faff00685d",
+ "metadata": {},
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "denied\n",
+ "is it locked inside the with? True\n",
+ "is it locked after the with? False\n"
+ ]
+ },
+ {
+ "data": {
+ "text/plain": [
+ "{'x': 5, 'y': 120, 'z': 200}"
+ ]
+ },
+ "execution_count": 7,
+ "metadata": {},
+ "output_type": "execute_result"
+ }
+ ],
+ "source": [
+ "transfer(\"x\", \"z\", 10)\n",
+ "bank_accounts"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 8,
+ "id": "41f9d7d2-86f8-433c-bf56-724a7f445753",
+ "metadata": {},
+ "outputs": [
+ {
+ "ename": "KeyError",
+ "evalue": "'w'",
+ "output_type": "error",
+ "traceback": [
+ "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+ "\u001b[0;31mKeyError\u001b[0m Traceback (most recent call last)",
+ "Cell \u001b[0;32mIn[8], line 1\u001b[0m\n\u001b[0;32m----> 1\u001b[0m \u001b[43mtransfer\u001b[49m\u001b[43m(\u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mw\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mz\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;241;43m10\u001b[39;49m\u001b[43m)\u001b[49m \u001b[38;5;66;03m# there is no \"w\" bank account\u001b[39;00m\n\u001b[1;32m 2\u001b[0m bank_accounts\n",
+ "Cell \u001b[0;32mIn[5], line 7\u001b[0m, in \u001b[0;36mtransfer\u001b[0;34m(src, dst, amount)\u001b[0m\n\u001b[1;32m 5\u001b[0m \u001b[38;5;28;01mwith\u001b[39;00m lock: \u001b[38;5;66;03m# automatically acquire now, automatically release after the with\u001b[39;00m\n\u001b[1;32m 6\u001b[0m success \u001b[38;5;241m=\u001b[39m \u001b[38;5;28;01mFalse\u001b[39;00m\n\u001b[0;32m----> 7\u001b[0m \u001b[38;5;28;01mif\u001b[39;00m \u001b[43mbank_accounts\u001b[49m\u001b[43m[\u001b[49m\u001b[43msrc\u001b[49m\u001b[43m]\u001b[49m \u001b[38;5;241m>\u001b[39m\u001b[38;5;241m=\u001b[39m amount:\n\u001b[1;32m 8\u001b[0m bank_accounts[src] \u001b[38;5;241m-\u001b[39m\u001b[38;5;241m=\u001b[39m amount\n\u001b[1;32m 9\u001b[0m bank_accounts[dst] \u001b[38;5;241m+\u001b[39m\u001b[38;5;241m=\u001b[39m amount\n",
+ "\u001b[0;31mKeyError\u001b[0m: 'w'"
+ ]
+ }
+ ],
+ "source": [
+ "transfer(\"w\", \"z\", 10) # there is no \"w\" bank account\n",
+ "bank_accounts"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 9,
+ "id": "f193975b-6f75-4c3c-b789-c494ad1130a6",
+ "metadata": {},
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "transferred\n",
+ "is it locked inside the with? True\n",
+ "is it locked after the with? False\n"
+ ]
+ },
+ {
+ "data": {
+ "text/plain": [
+ "{'x': 5, 'y': 170, 'z': 150}"
+ ]
+ },
+ "execution_count": 9,
+ "metadata": {},
+ "output_type": "execute_result"
+ }
+ ],
+ "source": [
+ "transfer(\"z\", \"y\", 50)\n",
+ "bank_accounts"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": null,
+ "id": "cd9dd92a-3d2c-47c7-85f1-4bec952d1a67",
+ "metadata": {},
+ "outputs": [],
+ "source": []
+ }
+ ],
+ "metadata": {
+ "kernelspec": {
+ "display_name": "Python 3.13-nogil",
+ "language": "python",
+ "name": "python3.13-nogil"
+ },
+ "language_info": {
+ "codemirror_mode": {
+ "name": "ipython",
+ "version": 3
+ },
+ "file_extension": ".py",
+ "mimetype": "text/x-python",
+ "name": "python",
+ "nbconvert_exporter": "python",
+ "pygments_lexer": "ipython3",
+ "version": "3.13.2"
+ }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}
--
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