On DTrace envy
Posted Aug 8, 2007 8:20 UTC (Wed) by njs
In reply to: On DTrace envy
Parent article: On DTrace envy
I don't understand this. The "predefined trace points" that DTrace provides are things like "thread blocked waiting on IO", "thread resumed after waiting on IO", "cpu went idle", "module was loaded", "page was swapped out". Sure Linux changes really fast, but... is it going to stop having threads that block on IO, cpus that go idle, modules that get loaded, and pages that get swapped out? Of course there is some work in maintaining high-level trace points like these as the actual code implementing the high-level events changes, but I don't see how it's an unreasonable amount of work, given the benefits.
Right now on Linux there is no way to take an app and profile its disk seeks in the same way that oprofile lets us profile its i-cache misses; on Solaris dtrace makes it trivial, including userspace stack traces (another oprofile feature, so still a fair comparison).
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