Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
DTrace: printf debugging for seventh-level wizards
Search
Shawn Moore
January 14, 2012
Programming
2
1.2k
DTrace: printf debugging for seventh-level wizards
Shawn Moore
January 14, 2012
Tweet
Share
More Decks by Shawn Moore
See All by Shawn Moore
Right the First Time
sartak
0
400
Lifting Moose
sartak
0
470
Kindergarten Code
sartak
0
77
How to be Fluent in Japanese
sartak
0
130
DTrace War Stories
sartak
1
110
Moose Role Usage Patterns
sartak
5
5.7k
git-status-tackle
sartak
5
330
Extending Moose for Applications
sartak
1
350
API Design
sartak
4
960
Other Decks in Programming
See All in Programming
feature環境をGitHub ActionsとCloudFormationでいい感じに管理する
nealle
2
310
データカタログ運用物語 〜令和6年夏の理想と現実〜
kuro_kurorrr
0
110
Terraformテスト入門
msato
0
540
Webエディタライブラリ 「CodeMirror」から学ぶ Webアプリ開発のテクニック
ryosukeigarashi
0
250
Modern Angular: Renovation for Your Applications
manfredsteyer
PRO
0
140
Rust.Nagoya #1
codemountains
0
170
Architectures with Lightweight Stores: New Rules and Options
manfredsteyer
PRO
0
100
SDCon2024: Enabling DevOps and Team Topologies thru architecture: architecting for fast flow
cer
PRO
0
780
なぜ宣言的 UI は壊れにくいのか / Why declarative UI is less fragile
uenitty
29
13k
3 Effective Rules for Success with Signals in Angular
manfredsteyer
PRO
0
120
CSC307 Lecture 13
javiergs
PRO
0
150
HMSコンペ 11th Solution (team : kansai-kaggler)
t88
1
680
Featured
See All Featured
Typedesign – Prime Four
hannesfritz
37
2.2k
It's Worth the Effort
3n
181
27k
Creating an realtime collaboration tool: Agile Flush - .NET Oxford
marcduiker
16
1.6k
Designing for Performance
lara
604
67k
Pencils Down: Stop Designing & Start Developing
hursman
118
11k
Documentation Writing (for coders)
carmenintech
63
4.2k
How GitHub (no longer) Works
holman
305
140k
"I'm Feeling Lucky" - Building Great Search Experiences for Today's Users (#IAC19)
danielanewman
224
21k
[Rails World 2023 - Day 1 Closing Keynote] - The Magic of Rails
eileencodes
17
1.5k
Optimizing for Happiness
mojombo
373
69k
How STYLIGHT went responsive
nonsquared
93
5k
Six Lessons from altMBA
skipperchong
24
3.2k
Transcript
@sartak DTRACE printf debugging for seventh-level wizards 121݄14༵
ME ME ME ME ME ME ME Shawn M Moore
@sartak I’m Bawstin’ Moose-lover Infinity Interactive 121݄14༵
What’s my computer doing right now? Q: A: Find out
with DTrace 121݄14༵
iotop $ iotop dtrace: failed to initialize dtrace: DTrace requires
additional privileges You may already have DTrace and not even know it. 121݄14༵
Solaris & OS X (complete) Linux (partial) Profiler (Different and
deeper than NYTProf) Debugger Kernel module “You don’t port DTrace to an OS, you port an OS to DTrace” DTRACE 121݄14༵
SAFE! ɾNo unwanted side effects ɾVery low overhead ɾDo it
in production! 121݄14༵
σϞ pidpersec iotop execsnoop opensnoop dtruss plockstat iosnoop Global (high
level) The metal (low level) 121݄14༵
σϞ pidpersec iotop execsnoop opensnoop dtruss plockstat iosnoop Global (high
level) The metal (low level) 121݄14༵
PROGRAMMABILITY dtrace -n ' syscall::open:entry /strstr(copyinstr(arg0), "corpus") != NULL/ {
printf("%s %s",execname,copyinstr(arg0)); }' Show processes that open a file whose name includes “corpus” 121݄14༵
PROGRAMMABILITY dtrace -n ' syscall::open:entry /strstr(copyinstr(arg0), "corpus") != NULL/ {
printf("%s %s",execname,copyinstr(arg0)); }' Show processes that open a file whose name includes “corpus” Event(Probe Description) 121݄14༵
PROGRAMMABILITY dtrace -n ' syscall::open:entry /strstr(copyinstr(arg0), "corpus") != NULL/ {
printf("%s %s",execname,copyinstr(arg0)); }' Show processes that open a file whose name includes “corpus” Predicate 121݄14༵
PROGRAMMABILITY dtrace -n ' syscall::open:entry /strstr(copyinstr(arg0), "corpus") != NULL/ {
printf("%s %s",execname,copyinstr(arg0)); }' Show processes that open a file whose name includes “corpus” Action 121݄14༵
PROGRAMMABILITY dtrace -n ' syscall::open:entry /strstr(copyinstr(arg0), "corpus") != NULL/ {
printf("%s %s",execname,copyinstr(arg0)); }' Show processes that open a file whose name includes “corpus” 121݄14༵
DTrace instrumentation points ɾKernel function calls/returns (syscalls too) ɾPerl function
calls/returns ɾSQL execution ɾthreads ɾsignals ɾmany more PROBES 121݄14༵
THE COOL DEMO HEY, FORGETFUL! DEMO THE GPG THING 121݄14༵
PROFILER Devel::NYTProf kicks ass 121݄14༵
PROFILER But there’s more than one way to do it
121݄14༵
PROFILER DEMO: syscalls intuit_method 121݄14༵
XCode’s profiler uses DTrace 121݄14༵
121݄14༵
TRANSLATION “I am comfortable being ignorant and helpless” 121݄14༵
DEBUGGER Request Tracker (e.g. rt.cpan.org) was failing tests on mod_perl.
On only my computer. Probably because of all the Japanese. 121݄14༵
DEBUGGER Failed test 'gpg: error reading key: ެ։伴͕ݟ͔ͭΓ·ͤΜ' doesn't match
'(?-xism:public key not found)' 121݄14༵
DEBUGGER ެ։伴͕ݟ͔ͭΓ·ͤΜ isn’t part of RT’s Japanese i18n 121݄14༵
DEBUGGER ެ։伴͕ݟ͔ͭΓ·ͤΜ possibly from GPG’s i18n? 121݄14༵
DEBUGGER gpg-2.0.18 $ ack -a ެ։伴͕ݟ͔ͭΓ·ͤΜ gpg-2.0.18 $ 121݄14༵
DEBUGGER gpg-2.0.18 $ echo "ެ։伴͕ݟ͔ͭΓ·ͤΜ" | iconv -f UTF-8 -t
EUCJP | xargs ack -ao | iconv -f EUCJP -t UTF-8 Binary file po/ja.gmo matches po/ja.po:2965:ެ։伴͕ݟ͔ͭΓ·ͤΜ po/ja.po:6525:ެ։伴͕ݟ͔ͭΓ·ͤΜ po/ja.po:8311:ެ։伴͕ݟ͔ͭΓ·ͤΜ gpg-2.0.18 $ 121݄14༵
DEBUGGER probably a mis-set $LANG, $LC_ALL? 121݄14༵
DEBUGGER Ͱ LC_ALL=en gpg LC_ALL=ja gpg LC_ALL= gpg opensnoop 121݄14༵
DEBUGGER Without DTrace, woulda had to add print statements to
GPG itself 121݄14༵
DEBUGGER then compiled it 121݄14༵
DEBUGGER then installed it 121݄14༵
DEBUGGER then repeated a couple of times because I’m a
“throw everything til something sticks” kinda guy 121݄14༵
DEBUGGER then cleaned up after all that hot mess 121݄14༵
DEBUGGER DTrace is great for debugging interactions between programs 121݄14༵
DEBUGGER DTrace is great for debugging interactions between YOUR BEAUTIFUL
CODE and THE IDIOTS 121݄14༵
Perl ɾ5.10.0+: sub-entry, sub-return ɾ5.15.1+: phase-change (${^GLOBAL_PHASE}) ɹ ɾFuture?: string
eval, etc. perldoc perldtrace 121݄14༵
Perl ɾ5.10.0Ҏ߱: sub-entry, sub-return ɾ5.15.1Ҏ߱: phase-change ɹ ɾকདྷʁ: string eval
My first Perl patch! Was simple! perldtrace 121݄14༵
QUESTIONS? ຊޠͰ̤̠Ͱ͢ʂ slides: http://twitter.com/sartak 121݄14༵