Re: [PATCH v2 10/29] ktap: add string handling code(kernel/trace/ktap/kp_[str|mempool].[c|h])

From: Andi Kleen
Date: Sun Mar 30 2014 - 13:20:08 EST


> See test/benchmark/cmp_table.sh, that script compare

Is that a realistic tracing scenario?

> table operation between ktap with stap, the result is very
> inspiring, ktap table operation overhead is quite lower than
> stap, especially when use constant string key.

Ok fair enough.

>
> But I agree with you partly, because in some cases we don't
> want/need to interning all string, for example:
> trace xxx:yyy {
> var str = cast("char *", arg1)
> print(str)
> }
>
> In above case, arg1 is a long kernel string, and no table insert,
> so definitely no need to interned, so we need to add
> KTAP_TRAWSTR to represent these values.

Please don't make it more complicated. If there's a good rationale
for interning it' ok to use always.

It would be better to find ways to simplify things.

-Andi
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