Search This Blog

2009-04-21

Threading Best Practices

STRAIGHT COPY PASTE FROM
STACKOVERFLOW - Threading Best Practices

Immutability is great for multi-threading. Functional programming works well concurrently partly due to the emphasis on immutability.
Use locks when you access mutable shared data, both for reads and writes.
Don't try to go lock-free unless you really have to. Locks are expensive, but rarely the bottleneck.
Monitor.Wait should almost always be part of a condition loop, waiting for a condition to become true and waiting again if it's not.
Try to avoid holding locks for longer than you need to.
If you ever need to acquire two locks at once, document the ordering thoroughly and make sure you always use the same order.
Document the thread-safety of your types. Most types don't need to be thread-safe, they just need to not be thread hostile (i.e. "you can use them from multiple threads, but it's your responsible for taking out locks if you want to share them)
Don't access the UI (except in documented thread-safe ways) from a non-UI thread. In Windows Forms, use Control.Invoke/BeginInvoke


Before jumping into it, first understand that the the class boundary is not the same as a thread boundary. For example, if a callback method on your class is called by another thread (e.g., the AsyncCallback delegate to the TcpListener.BeginAcceptTcpClient() method), understand that the callback executes on that other thread. So even though the callback occurs on the same object, you still have to synchronize access to the members of the object within the callback method. Threads and classes are orthogonal; it is important to understand this point.
Identify what data needs to be shared between threads. Once you have defined the shared data, try to consolidate it into a single class if possible.
Limit the places where the shared data can be written and read. If you can get this down to one place for writing and one place for reading, you will be doing yourself a tremendous favor. This is not always possible, but it is a nice goal to shoot for.
Obviously make sure you synchronize access to the shared data using the Monitor class or the lock keyword.
If possible, use a single object to synchronize your shared data regardless of how many different shared fields there are. This will simplify things. However, it may also overly constrain things too, in which case, you may need a synchronization object for each shared field. And at this point, using immutable classes becomes very handy.
If you have one thread that needs to signal another thread(s), I would strongly recommend using the ManualResetEvent class to do this instead of using events/delegates.

Labels

perl (41) Cheat Sheet (25) how-to (24) windows (14) sql server 2008 (13) linux (12) oracle (12) sql (12) Unix (11) cmd windows batch (10) mssql (10) cmd (9) script (9) textpad (9) netezza (8) sql server 2005 (8) cygwin (7) meta data mssql (7) metadata (7) bash (6) code generation (6) Informatica (5) cheatsheet (5) energy (5) tsql (5) utilities (5) excel (4) future (4) generic (4) html (4) perl modules (4) programs (4) settings (4) sh (4) shortcuts (4) поуки (4) принципи (4) Focus Fusion (3) Solaris (3) cool programs (3) development (3) economy (3) example (3) freeware (3) fusion (3) git cheat sheet (3) logging (3) morphus (3) mssql 2005 (3) nuclear (3) nz (3) parse (3) python (3) sftp (3) sofware development (3) source (3) sqlplus (3) table (3) vim (3) .Net (2) C# (2) China (2) GUI (2) Google (2) GoogleCL (2) Solaris Unix (2) ascii (2) awk (2) batch (2) cas (2) chrome extensions (2) code2html (2) columns (2) configuration (2) conversion (2) duplicates (2) excel shortcuts (2) export (2) file (2) free programs (2) informatica sql repository (2) linux cheat sheet (2) mssql 2008 (2) mysql (2) next big future (2) nsis (2) nz netezza cheat sheet (2) nzsql (2) ora (2) prediction (2) publish (2) release management (2) report (2) security (2) single-click (2) sqlserver 2005 (2) sqlserver 2008 (2) src (2) ssh (2) template (2) tools (2) vba (2) video (2) xlt (2) xml (2) youtube videos (2) *nix (1) .vimrc (1) .virmrc vim settings configs (1) BSD license (1) Bulgaria (1) Dallas (1) Database role (1) Dense plasma focus (1) Deployment (1) ERP (1) ExcelToHtml (1) GD (1) GDP (1) HP-UX (1) Hosting (1) INC (1) IT general (1) ITIL management bullshit-management (1) IZarc (1) Java Web Start (1) JavaScript anchor html jquery (1) Khan Academy (1) LINUX UNIX BASH AND CYGWIN TIPS AND TRICKS (1) Linux Unix rpm cpio build install configure (1) Linux git source build .configure make (1) ListBox (1) MIT HYDROGEN VIRUS (1) OO (1) Obama (1) PowerShell (1) Run-time (1) SDL (1) SIWA (1) SOX (1) Scala (1) Services (1) Stacks (1) SubSonic (1) TED (1) abstractions (1) ansible hosts linux bash (1) ansible linux deployment how-to (1) ansible yum pip python (1) apache (1) apache 2.2 (1) application life cycle (1) architecture (1) archive (1) arguments (1) avatar (1) aws cheat sheet cli (1) aws cli (1) aws cli amazon cheat sheet (1) aws elb (1) backup (1) bash Linux open-ssh ssh ssh_server ssh_client public-private key authentication (1) bash perl search and replace (1) bash stub (1) bin (1) biofuels (1) biology (1) books (1) browser (1) bubblesort (1) bugs (1) build (1) byte (1) cas_sql_dev (1) chennai (1) chrome (1) class (1) claut (1) cmdow (1) code generation sqlserver (1) command (1) command line (1) conf (1) confluence (1) console (1) convert (1) cool programs windows free freeware (1) copy-paste (1) csv (1) ctags (1) current local time (1) cygwin X11 port-forwarding mintty xclock Linux Unix X (1) cygwin bash how-to tips_n_tricks (1) cygwin conf how-to (1) data (1) data types (1) db2 cheat sheet (1) db2 starter ibm bash Linux (1) debt (1) diagram (1) dictionaries (1) digital (1) disk (1) disk space (1) documentation (1) dos (1) dubai (1) e-cars (1) electric cars (1) electricity (1) emulate (1) errors (1) exponents (1) export workflow (1) extract (1) fast export (1) fexp (1) file extension (1) file permissions (1) findtag (1) firewall (1) for loop (1) freaky (1) functions (1) fusion research (1) german (1) git gitlab issues handling system (1) google cli (1) google code (1) google command line interface (1) gpg (1) ha (1) head (1) helsinki (1) history (1) hop or flop (1) host-independant (1) how-to Windows cmd time date datetime (1) ibm db2 cognos installation example db deployment provisioning (1) ideas (1) image (1) informatica oracle sql (1) informatica repo sql workflows sessions file source dir (1) informatica source files etl (1) install (1) isg-pub issue-tracker architecture (1) it management best practices (1) java (1) jump to (1) keyboard shortcuts (1) ksh (1) level (1) linkedin (1) linux bash ansible hosts (1) linux bash commands (1) linux bash how-to shell expansion (1) linux bash shell grep xargs (1) linux bash tips and t ricks (1) linux bash unix cygwin cheatsheet (1) linux bash user accounts password (1) linux bash xargs space (1) linux cheat-sheet (1) linux cheatsheet cheat-sheet revised how-to (1) linux how-to non-root vim (1) linux ssh hosts parallel subshell bash oneliner (1) london (1) make (1) me (1) metacolumn (1) metadata functions (1) metaphonre (1) method (1) model (1) movie (1) multithreaded (1) mysql cheat sheet (1) mysql how-to table datatypes (1) n900 (1) nano (1) neteza (1) netezza bash linux nps (1) netezza nps (1) netezza nps nzsql (1) netezza nz Linux bash (1) netezza nz bash linux (1) netezza nz nzsql sql (1) netezza nzsql database db sizes (1) non-password (1) nord pol (1) nps backup nzsql schema (1) number formatting (1) nz db size (1) nz table count rows (1) nzsql date timestamp compare bigint to_date to_char now (1) on-lier (1) one-liners (1) one-to-many (1) oneliners (1) open (1) open source (1) openrowset (1) openssl (1) oracle PL/SQL (1) oracle Perl perl (1) oracle installation usability (1) oracle number formatting format-model ora-sql oracle (1) oracle templates create table (1) oracle trigger generic autoincrement (1) oracle vbox virtual box cheat sheet (1) oracle virtual box cheat sheet (1) outlook (1) parser (1) password (1) paths (1) perl @INC compile-time run-time (1) perl disk usage administration Linux Unix (1) perl modules configuration management (1) permissions (1) php (1) picasa (1) platform (1) postgreSQL how-to (1) powerShell cmd cygwin mintty.exe terminal (1) ppm (1) predictions (1) prices (1) principles (1) productivity (1) project (1) prompt (1) proxy account (1) public private key (1) publishing (1) putty (1) qt (1) read file (1) registry (1) relationship (1) repository (1) rm (1) scp (1) scripts (1) scsi (1) search and replace (1) sed (1) sendEmail (1) sh stub (1) shortcuts Windows sql developer Oracle (1) sidebar (1) silicon (1) smtp (1) software procurement (1) sofware (1) sort (1) sql script (1) sql_dev (1) sqlcmd (1) sqlite (1) sqlite3 (1) sshd (1) sshd cygwin (1) stackoverflow (1) stored procedure (1) stub (1) stupidity (1) subroutines (1) svn (1) sysinternals (1) tail (1) tar (1) temp table (1) templates (1) teradata (1) terminal (1) test (1) testing (1) theory (1) thorium (1) time (1) tip (1) title (1) tmux .tmux.conf configuration (1) tmux efficiency bash (1) tool (1) ui code prototyping tips and tricks (1) umask Linux Unix bash file permissions chmod (1) url (1) urls (1) user (1) utility (1) utils (1) vb (1) vbox virtual box cheat sheet (1) vim perl regex bash search for string (1) vim recursively hacks (1) vim starter (1) vim-cheat-sheet vim cheat-sheet (1) vimeo (1) visual stuio (1) warsaw (1) wiki (1) wikipedia (1) window (1) windows 7 (1) windows 8 (1) windows programs (1) windows reinstall (1) windows utility batch perl space Windows::Clipboard (1) wisdoms (1) workflow (1) worth-reading (1) wrapper (1) xp_cmdshell (1) xslt (1) youtube (1)

Blog Archive

Translate with Google Translate

My Blog List

VideoBar

This content is not yet available over encrypted connections.