1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 \documentclass[14pt]{beamer} \usepackage{hyperref} \usepackage{fancyvrb} \makeatletter \def\PY@reset{\let\PY@it=\relax \let\PY@bf=\relax% \let\PY@ul=\relax \let\PY@tc=\relax% \let\PY@bc=\relax \let\PY@ff=\relax} \def\PY@tok#1{\csname PY@tok@#1\endcsname} \def\PY@toks#1+{\ifx\relax#1\empty\else% \PY@tok{#1}\expandafter\PY@toks\fi} \def\PY@do#1{\PY@bc{\PY@tc{\PY@ul{% \PY@it{\PY@bf{\PY@ff{#1}}}}}}} \def\PY#1#2{\PY@reset\PY@toks#1+\relax+\PY@do{#2}} \def\PY@tok@gd{\def\PY@bc##1{\fcolorbox[rgb]{0.80,0.00,0.00}{1.00,0.80,0.80}{##1}}} \def\PY@tok@gu{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.00,0.20,0.00}{##1}}} \def\PY@tok@gt{\def\PY@tc##1{\textcolor[rgb]{0.60,0.80,0.40}{##1}}} \def\PY@tok@gs{\let\PY@bf=\textbf} \def\PY@tok@gr{\def\PY@tc##1{\textcolor[rgb]{1.00,0.00,0.00}{##1}}} \def\PY@tok@cm{\let\PY@it=\textit\def\PY@tc##1{\textcolor[rgb]{0.00,0.60,1.00}{##1}}} \def\PY@tok@vg{\def\PY@tc##1{\textcolor[rgb]{0.00,0.20,0.20}{##1}}} \def\PY@tok@m{\def\PY@tc##1{\textcolor[rgb]{1.00,0.40,0.00}{##1}}} \def\PY@tok@mh{\def\PY@tc##1{\textcolor[rgb]{1.00,0.40,0.00}{##1}}} \def\PY@tok@cs{\let\PY@bf=\textbf\let\PY@it=\textit\def\PY@tc##1{\textcolor[rgb]{0.00,0.60,1.00}{##1}}} \def\PY@tok@ge{\let\PY@it=\textit} \def\PY@tok@vc{\def\PY@tc##1{\textcolor[rgb]{0.00,0.20,0.20}{##1}}} \def\PY@tok@il{\def\PY@tc##1{\textcolor[rgb]{1.00,0.40,0.00}{##1}}} \def\PY@tok@go{\def\PY@tc##1{\textcolor[rgb]{0.67,0.67,0.67}{##1}}} \def\PY@tok@cp{\def\PY@tc##1{\textcolor[rgb]{0.00,0.60,0.60}{##1}}} \def\PY@tok@gi{\def\PY@bc##1{\fcolorbox[rgb]{0.00,0.80,0.00}{0.80,1.00,0.80}{##1}}} \def\PY@tok@gh{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.00,0.20,0.00}{##1}}} \def\PY@tok@ni{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.60,0.60,0.60}{##1}}} \def\PY@tok@nl{\def\PY@tc##1{\textcolor[rgb]{0.60,0.60,1.00}{##1}}} \def\PY@tok@nn{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.00,0.80,1.00}{##1}}} \def\PY@tok@no{\def\PY@tc##1{\textcolor[rgb]{0.20,0.40,0.00}{##1}}} \def\PY@tok@na{\def\PY@tc##1{\textcolor[rgb]{0.20,0.00,0.60}{##1}}} \def\PY@tok@nb{\def\PY@tc##1{\textcolor[rgb]{0.20,0.40,0.40}{##1}}} \def\PY@tok@nc{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.00,0.67,0.53}{##1}}} \def\PY@tok@nd{\def\PY@tc##1{\textcolor[rgb]{0.60,0.60,1.00}{##1}}} \def\PY@tok@ne{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.80,0.00,0.00}{##1}}} \def\PY@tok@nf{\def\PY@tc##1{\textcolor[rgb]{0.80,0.00,1.00}{##1}}} \def\PY@tok@si{\def\PY@tc##1{\textcolor[rgb]{0.67,0.00,0.00}{##1}}} \def\PY@tok@s2{\def\PY@tc##1{\textcolor[rgb]{0.80,0.20,0.00}{##1}}} \def\PY@tok@vi{\def\PY@tc##1{\textcolor[rgb]{0.00,0.20,0.20}{##1}}} \def\PY@tok@nt{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.20,0.00,0.60}{##1}}} \def\PY@tok@nv{\def\PY@tc##1{\textcolor[rgb]{0.00,0.20,0.20}{##1}}} \def\PY@tok@s1{\def\PY@tc##1{\textcolor[rgb]{0.80,0.20,0.00}{##1}}} \def\PY@tok@gp{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.00,0.00,0.60}{##1}}} \def\PY@tok@sh{\def\PY@tc##1{\textcolor[rgb]{0.80,0.20,0.00}{##1}}} \def\PY@tok@ow{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.00,0.00,0.00}{##1}}} \def\PY@tok@sx{\def\PY@tc##1{\textcolor[rgb]{0.80,0.20,0.00}{##1}}} \def\PY@tok@bp{\def\PY@tc##1{\textcolor[rgb]{0.20,0.40,0.40}{##1}}} \def\PY@tok@c1{\let\PY@it=\textit\def\PY@tc##1{\textcolor[rgb]{0.00,0.60,1.00}{##1}}} \def\PY@tok@kc{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.00,0.40,0.60}{##1}}} \def\PY@tok@c{\let\PY@it=\textit\def\PY@tc##1{\textcolor[rgb]{0.00,0.60,1.00}{##1}}} \def\PY@tok@mf{\def\PY@tc##1{\textcolor[rgb]{1.00,0.40,0.00}{##1}}} \def\PY@tok@err{\def\PY@tc##1{\textcolor[rgb]{0.67,0.00,0.00}{##1}}\def\PY@bc##1{\colorbox[rgb]{1.00,0.67,0.67}{##1}}} \def\PY@tok@kd{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.00,0.40,0.60}{##1}}} \def\PY@tok@ss{\def\PY@tc##1{\textcolor[rgb]{1.00,0.80,0.20}{##1}}} \def\PY@tok@sr{\def\PY@tc##1{\textcolor[rgb]{0.20,0.67,0.67}{##1}}} \def\PY@tok@mo{\def\PY@tc##1{\textcolor[rgb]{1.00,0.40,0.00}{##1}}} \def\PY@tok@mi{\def\PY@tc##1{\textcolor[rgb]{1.00,0.40,0.00}{##1}}} \def\PY@tok@kn{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.00,0.40,0.60}{##1}}} \def\PY@tok@o{\def\PY@tc##1{\textcolor[rgb]{0.33,0.33,0.33}{##1}}} \def\PY@tok@kr{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.00,0.40,0.60}{##1}}} \def\PY@tok@s{\def\PY@tc##1{\textcolor[rgb]{0.80,0.20,0.00}{##1}}} \def\PY@tok@kp{\def\PY@tc##1{\textcolor[rgb]{0.00,0.40,0.60}{##1}}} \def\PY@tok@w{\def\PY@tc##1{\textcolor[rgb]{0.73,0.73,0.73}{##1}}} \def\PY@tok@kt{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.00,0.47,0.53}{##1}}} \def\PY@tok@sc{\def\PY@tc##1{\textcolor[rgb]{0.80,0.20,0.00}{##1}}} \def\PY@tok@sb{\def\PY@tc##1{\textcolor[rgb]{0.80,0.20,0.00}{##1}}} \def\PY@tok@k{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.00,0.40,0.60}{##1}}} \def\PY@tok@se{\let\PY@bf=\textbf\def\PY@tc##1{\textcolor[rgb]{0.80,0.20,0.00}{##1}}} \def\PY@tok@sd{\let\PY@it=\textit\def\PY@tc##1{\textcolor[rgb]{0.80,0.20,0.00}{##1}}} \def\PYZbs{\char\\} \def\PYZus{\char\_} \def\PYZob{\char\{} \def\PYZcb{\char\}} \def\PYZca{\char\^} \def\PYZsh{\char\#} \def\PYZpc{\char\%} \def\PYZdl{\char\\$} \def\PYZti{\char\~} % for compatibility with earlier versions \def\PYZat{@} \def\PYZlb{[} \def\PYZrb{]} \makeatother \definecolor{rrblitbackground}{rgb}{0.55, 0.3, 0.1} \newenvironment{rtbliteral}{ \begin{ttfamily} \color{rrblitbackground} }{ \end{ttfamily} } % generated by Docutils \usepackage{fixltx2e} % LaTeX patches, \textsubscript \usepackage{cmap} % fix search and cut-and-paste in Acrobat \usepackage{ifthen} \usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage{graphicx} %%% Custom LaTeX preamble % PDF Standard Fonts \usepackage{mathptmx} % Times \usepackage[scaled=.90]{helvet} \usepackage{courier} %%% User specified packages and stylesheets \input{stylesheet.latex} %%% Fallback definitions for Docutils-specific commands % hyperlinks: \ifthenelse{\isundefined{\hypersetup}}{ \usepackage[colorlinks=true,linkcolor=blue,urlcolor=blue]{hyperref} \urlstyle{same} % normal text font (alternatives: tt, rm, sf) }{} \hypersetup{ pdftitle={Software Transactional Memory for real''}, } %%% Title Data \title{\phantomsection% Software Transactional Memory for real''% \label{software-transactional-memory-for-real}} \author{} \input{author.latex} %%% Body \begin{document} \input{title.latex} % colors % =========================== % general useful commands % =========================== % closed bracket % =========================== % example block % =========================== % alert block % =========================== % columns % =========================== % nested blocks % =========================== \begin{frame} \frametitle{Introduction} % \begin{itemize} \item This talk is about programming multi- or many-core machines \end{itemize} \end{frame} \begin{frame} \frametitle{About myself} % \begin{itemize} \item Armin Rigo \item Language implementation guy'' \end{itemize} \pause % \begin{itemize} \item PyPy project % \begin{itemize} \item Python in Python \item includes a Just-in-Time Compiler Generator'' for Python and any other dynamic language \end{itemize} \end{itemize} \end{frame} \begin{frame} \frametitle{Motivation} % \begin{itemize} \item A single-core program is getting exponentially slower than a multi-core one \end{itemize} \pause % \begin{itemize} \item Using several processes exchanging data % \begin{itemize} \item works fine in some cases \item but becomes a large mess in others \end{itemize} \end{itemize} \pause % \begin{itemize} \item Using several threads % \begin{itemize} \item this talk! \end{itemize} \end{itemize} \end{frame} \begin{frame} \frametitle{Common solution} % \begin{itemize} \item Organize your program in multiple threads \item Add synchronization when accessing shared, non-read-only data \end{itemize} \end{frame} \begin{frame} \frametitle{Synchronization with locks} % \begin{itemize} \item Carefully place locks around every access to shared data \end{itemize} \pause % \begin{itemize} \item How do you know if you missed a place? % \begin{itemize} \item hard to catch by writing tests \item instead you get obscure rare run-time crashes \end{itemize} \end{itemize} \pause % \begin{itemize} \item Issues when scaling to a large program % \begin{itemize} \item order of acquisition \item deadlocks \end{itemize} \end{itemize} \end{frame} \begin{frame}[containsverbatim,fragile] \frametitle{Synchronization with TM} % \begin{itemize} \item TM = Transactional Memory \end{itemize} \pause \begin{Verbatim}[commandchars=\\\{\}] ---------------- -------------------- Locks Transactional Memory ---------------- -------------------- mylock.acquire(); atomic \PYZob{} x = list1.pop(); x = list1.pop(); list2.append(x); list2.append(x); mylock.release(); \PYZcb{} \end{Verbatim} \end{frame} \begin{frame} \frametitle{Locks versus TM} % \begin{itemize} \item Locks \end{itemize} \noindent\makebox[\textwidth][c]{\includegraphics[scale=0.700000]{withlock.png}} % \begin{itemize} \item TM \end{itemize} \noindent\makebox[\textwidth][c]{\includegraphics[scale=0.700000]{withstm0.png}} \end{frame} \begin{frame} \frametitle{Locks versus TM} % \begin{itemize} \item Locks \end{itemize} \noindent\makebox[\textwidth][c]{\includegraphics[scale=0.700000]{withlock.png}} % \begin{itemize} \item TM in case of conflict \end{itemize} \noindent\makebox[\textwidth][c]{\includegraphics[scale=0.700000]{withstm.png}} \end{frame} \begin{frame} \frametitle{Synchronization with TM} % \begin{itemize} \item Optimistic'' approach: % \begin{itemize} \item no lock to protect shared data in memory \item instead, track all memory accesses \item detect actual conflicts \item if conflict, restart the whole transaction'' \end{itemize} \end{itemize} \pause % \begin{itemize} \item Easier to use % \begin{itemize} \item no need to name locks \item no deadlocks \item composability'' \end{itemize} \end{itemize} \end{frame} \begin{frame} \frametitle{HTM versus STM} % \begin{itemize} \item HTM = Hardware Transactional Memory % \begin{itemize} \item Intel Haswell CPU, 2013 \item and others \end{itemize} \end{itemize} \pause % \begin{itemize} \item STM = Software Transactional Memory % \begin{itemize} \item various approaches \item large overhead (2x-10x), but getting faster \item experimental in PyPy: read/write barriers, as with GC \end{itemize} \end{itemize} \end{frame} \begin{frame} \frametitle{The catch} \pause % \begin{itemize} \item You Still Have To Use Threads \end{itemize} \pause % \begin{itemize} \item Threads are hard to debug, non-reproductible \end{itemize} \pause % \begin{itemize} \item Threads are Messy \end{itemize} \end{frame} \begin{frame} \frametitle{Issue with threads} % \begin{itemize} \item TM does not solve this problem: \item How do you know if you missed a place to put \texttt{atomic} around? % \begin{itemize} \item hard to catch by writing tests \item instead you get obscure rare run-time crashes \end{itemize} \end{itemize} \pause % \begin{itemize} \item What if we put \texttt{atomic} everywhere? \end{itemize} \end{frame} \begin{frame} \frametitle{Analogy with Garbage Collection} % \begin{itemize} \item Explicit Memory Management: % \begin{itemize} \item messy, hard to debug rare leaks or corruptions \end{itemize} \end{itemize} \pause % \begin{itemize} \item Automatic GC solves it % \begin{itemize} \item common languages either have a GC or not \item if they have a GC, it controls almost \emph{all} objects \item not just a small part of them \end{itemize} \end{itemize} \end{frame} \begin{frame} \frametitle{Proposed solution} % \begin{itemize} \item Put \texttt{atomic} everywhere... \item in other words, Run Everything with TM \end{itemize} \end{frame} \begin{frame} \frametitle{Proposed solution} % \begin{itemize} \item Really needs TM. With locks, you'd get this: \end{itemize} \noindent\makebox[\textwidth][c]{\includegraphics[scale=0.700000]{GIL.png}} % \begin{itemize} \item With TM you can get this: \end{itemize} \noindent\makebox[\textwidth][c]{\includegraphics[scale=0.700000]{STM.png}} \end{frame} \begin{frame} \frametitle{In a few words} % \begin{itemize} \item Longer transactions \item Corresponding to larger parts of the program \item The underlying multi-threaded model becomes implicit \end{itemize} \end{frame} \begin{frame} \frametitle{Typical example} % \begin{itemize} \item You want to run \texttt{f1()} and \texttt{f2()} and \texttt{f3()} \end{itemize} \pause % \begin{itemize} \item Assume they are mostly independent'' % \begin{itemize} \item i.e. we expect that we can run them in parallel \item but we cannot prove it, we just hope that in the common case we can \end{itemize} \end{itemize} \pause % \begin{itemize} \item In case of conflicts, we don't want random behavior % \begin{itemize} \item i.e. we don't want thread-like non-determinism and crashes \end{itemize} \end{itemize} \end{frame} \begin{frame} \frametitle{Pooling and atomic statements} % \begin{itemize} \item Solution: use a library that creates a pool of threads \item Each thread picks a function from the list and runs it with \texttt{atomic} \end{itemize} \end{frame} \begin{frame} \frametitle{Results} % \begin{itemize} \item The behavior is as if'' we had run \texttt{f1()}, \texttt{f2()} and \texttt{f3()} sequentially \item The programmer chooses if he wants this fixed order, or if any order is fine \item Threads are hidden from the programmer \end{itemize} \end{frame} \begin{frame} \frametitle{More generally} % \begin{itemize} \item This was an example only \item \textbf{TM gives various new ways to hide threads under a nice interface} \end{itemize} \end{frame} \begin{frame} \frametitle{Not the Ultimate Solution} % \begin{itemize} \item Much easier for the programmer to get reproducible results \item But maybe too many conflicts \end{itemize} \pause % \begin{itemize} \item The right side'' of the problem % \begin{itemize} \item start with a working program, and improve performance \item as opposed to: with locks, start with a fast program, and debug crashes \item we will need new debugging tools \end{itemize} \end{itemize} \end{frame} \begin{frame} \frametitle{PyPy-STM} % \begin{itemize} \item PyPy-STM: a version of PyPy with Software Transactional Memory % \begin{itemize} \item in-progress, but basically working \end{itemize} \item \url{http://pypy.org/} \end{itemize} \pause % \begin{itemize} \item Thank you! \end{itemize} \end{frame} \end{document} `