Re: [patch] Latency Tracer, voluntary-preempt-2.6.8-rc4-O6

[Andi Kleen]

> The final algorithm pre-calculates markers on the compressed symbols so 
> that the search time is almost divided by the number of markers.

You could do that at compile time (in scripts/kallsyms.c) 

> 
> There are still a few issues with this approach. The biggest issue is 
> that this is clearly a speed/space trade-off, and maybe we don't want to 
> waste the space on a code path that is not supposed to be "hot". If this 
> is the case, I can make a smaller patch, that fixes just the name 
> "decompression" strcpy's.

I'm surprised that using 8 markers helps anything. There should 
be many many more 0 stems than that in a not so big kernel.
Did you actually measure the hit rate of the cache? I bet it is pretty low.

-Andi
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/