Messages in this thread | | | Date | Fri, 06 Aug 2010 15:18:31 +0900 | From | Masami Hiramatsu <> | Subject | Re: [patch 1/2] x86_64 page fault NMI-safe |
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Peter Zijlstra wrote: > On Wed, 2010-08-04 at 10:45 -0400, Mathieu Desnoyers wrote: > >> How do you plan to read the data concurrently with the writer overwriting the >> data while you are reading it without corruption ? > > I don't consider reading while writing (in overwrite mode) a valid case. > > If you want to use overwrite, stop the writer before reading it.
For example, would you like to read system audit log always after stop the audit?
NO, that's a most important requirement for tracers, especially for system admins (they're the most important users of Linux) to check the system health and catch system troubles.
For performance measurement and checking hotspot, one-shot tracing is enough. But it's just for developers. But for the real world computing, Linux is just an OS, users want to run their system, middleware and applications, without troubles. But when they hit a trouble, they wanna shoot it ASAP. The flight recorder mode is mainly for those users.
Thank you,
-- Masami HIRAMATSU 2nd Research Dept. Hitachi, Ltd., Systems Development Laboratory E-mail: masami.hiramatsu.pt@hitachi.com
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