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1 parent a435391 commit 62eb199a1801314edc56f911db144d46f40fab22 Brendan Gregg committed Nov 21, 2013
Showing with 2 additions and 2 deletions.
  1. +2 −2 README
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4 README
@@ -21,11 +21,11 @@ Using DTrace to capture 60 seconds of kernel stacks at 997 Hertz:
Using DTrace to capture 60 seconds of user-level stacks for PID 12345 at 97 Hertz:
-# dtrace -x ustackframes=100 -n 'profile-97 /PID == 12345 && arg1/ { @[ustack()] = count(); } tick-60s { exit(0); }' -o out.user_stacks
+# dtrace -x ustackframes=100 -n 'profile-97 /pid == 12345 && arg1/ { @[ustack()] = count(); } tick-60s { exit(0); }' -o out.user_stacks
Using DTrace to capture 60 seconds of user-level stacks, including while time is spent in the kernel, for PID 12345 at 97 Hertz:
-# dtrace -x ustackframes=100 -n 'profile-97 /PID == 12345/ { @[ustack()] = count(); } tick-60s { exit(0); }' -o out.user_stacks
+# dtrace -x ustackframes=100 -n 'profile-97 /pid == 12345/ { @[ustack()] = count(); } tick-60s { exit(0); }' -o out.user_stacks
Switch ustack() for jstack() if the application has a ustack helper to include translated frames (eg, node.js frames; see: http://dtrace.org/blogs/dap/2012/01/05/where-does-your-node-program-spend-its-time/). The rate for user-level stack collection is deliberately slower than kernel, which is especially important when using jstack() as it performs additional work to translate frames.

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