Re: [PATCH -tip v7 24/26] kprobes: Enlarge hash table to 4096 entries

[Masami Hiramatsu]

(2014/02/28 6:45), Andi Kleen wrote:
> Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx> writes:
> 
>> Currently, since the kprobes expects to be used
>> with less than 100 probe points, its hash table
>> just has 64 entries. This is too little to handle
>> several thousands of probes.
>> Enlarge this to 4096 entires which just consumes
>> 32KB (on 64bit arch) for better scalability.
> 
> 32K for a debug feature that most systems never use seems
> too large to me.
> 
> First can you check if smaller hash tables work too
> (perhaps with a better hash, like jhash) 

I doubt jhash helps it, but yes, at least the various size
should be tested.

> And then if you enlarge the table please allocate
> it dynamically on the first use.

OK, I'll try to do so.

Thank you,

-- 
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx


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