Messages in this thread | | | Date | Tue, 13 Sep 2016 08:18:02 -0500 | From | Josh Poimboeuf <> | Subject | Re: [PATCH v3 01/15] x86/dumpstack: Optimize save_stack_trace |
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On Tue, Sep 13, 2016 at 06:45:00PM +0900, Byungchul Park wrote: > Currently, x86 implementation of save_stack_trace() is walking all stack > region word by word regardless of what the trace->max_entries is. > However, it's unnecessary to walk after already fulfilling caller's > requirement, say, if trace->nr_entries >= trace->max_entries is true. > > I measured its overhead and printed its difference of sched_clock() with > my QEMU x86 machine. The latency was improved over 70% when > trace->max_entries = 5.
This code will (probably) be obsoleted soon with my new unwinder.
Also, my previous comment was ignored:
Instead of adding a new callback, why not just check the ops->address() return value? It already returns an error if the array is full.
I think that would be cleaner and would help prevent more callback sprawl.
-- Josh
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