Re: [ltt-dev] Re: [PATCH] LTT for 2.5.38 1/9: Core infrastructure

Ingo Molnar (mingo@elte.hu)
Mon, 23 Sep 2002 01:02:46 +0200 (CEST)


On Sun, 22 Sep 2002, bob wrote:

> [...] On a technical note: a cache-line ping-ponging is bad - a global
> spinlock is horrendous. They're different - the lock-less MP scheme gets
> rid of them both.

(on the contrary - a global spinlock is bad for exactly that reason,
because it causes a cacheline ping-pong. So if two CPUs are trying to
write trace events at once, you'll get the same effect as if they were
using a global spinlock.)

Ingo

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