Re: [PATCH] fs: pipe/sockets/anon dentries should not have a parent

[Ingo Molnar]

* Eric Dumazet <dada1@xxxxxxxxxxxxx> wrote:

> Ingo Molnar a écrit :
>> * Eric Dumazet <dada1@xxxxxxxxxxxxx> wrote:
>>
>>> Before patch, time to run 8 millions of close(socket()) calls on 8  
>>> CPUS was :
>>>
>>> real    0m27.496s
>>> user    0m0.657s
>>> sys     3m39.092s
>>>
>>> After patch :
>>>
>>> real    0m23.997s
>>> user    0m0.682s
>>> sys     3m11.193s
>>
>> cool :-)
>>
>> What would it take to get it down to:
>>
>>>> Cost if run one one cpu :
>>>>
>>>> real    0m1.561s
>>>> user    0m0.092s
>>>> sys     0m1.469s
>>
>> i guess asking for a wall-clock cost of 1.561/8 would be too much? :)
>>
>
> It might be possible, depending on the level of hackery I am allowed 
> to inject in fs/dcache.c and fs/inode.c :)

I think being able to open+close sockets in a scalable way is an 
undisputed prime-time workload on Linux. The numbers you showed look 
horrible.

Once you can show how much faster it could go via hacks, it should 
only be a matter of time to achieve that safely and cleanly.

> wall cost of 1.56 (each cpu runs one loop of one million iterations)

(indeed.)

	Ingo
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