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

Ingo Molnar
2002-09-22T22:49:42Z

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