From: Nathan Zimmer <nzimmer@sgi.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: <linux-kernel@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>,
<adobriyan@gmail.com>, Alexander Viro <viro@zeniv.linux.org.uk>,
David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH] fs/proc: Move kfree outside pde_unload_lock
Date: Fri, 24 Aug 2012 11:45:45 -0500 [thread overview]
Message-ID: <5037AFB9.5010001@sgi.com> (raw)
In-Reply-To: <1345820311.4824.2.camel@edumazet-laptop>
On 08/24/2012 09:58 AM, Eric Dumazet wrote:
> Le vendredi 24 août 2012 à 09:48 -0500, Nathan Zimmer a écrit :
>> On Wed, Aug 22, 2012 at 11:42:58PM +0200, Eric Dumazet wrote:
>>> On Wed, 2012-08-22 at 20:28 +0200, Eric Dumazet wrote:
>>>
>>>> Thats interesting, but if you really want this to fly, one RCU
>>>> conversion would be much better ;)
>>>>
>>>> pde_users would be an atomic_t and you would avoid the spinlock
>>>> contention.
>>> Here is what I had in mind, I would be interested to know how it helps a 512 core machine ;)
>>>
>> Here are the results and they look great.
>>
>> cpuinfo baseline moved kfree Rcu
>> tasks read-sec read-sec read-sec
>> 1 0.0141 0.0141 0.0141
>> 2 0.0140 0.0140 0.0142
>> 4 0.0140 0.0141 0.0141
>> 8 0.0145 0.0145 0.0140
>> 16 0.0553 0.0548 0.0168
>> 32 0.1688 0.1622 0.0549
>> 64 0.5017 0.3856 0.1690
>> 128 1.7005 0.9710 0.5038
>> 256 5.2513 2.6519 2.0804
>> 512 8.0529 6.2976 3.0162
>>
>>
>>
> Indeed...
>
> Could you explicit the test you are actually doing ?
>
> Thanks
>
>
It is a dead simple test.
The test starts by forking off X number of tasks
assigning each their own cpu.
Each task then allocs a bit of memory.
All tasks wait on a memory cell for the go order.
We measure the read time starting here.
Once the go order is given they all read a chunk of the selected proc file.
I was using /proc/cpuinfo to test.
Once everyone has finished we take the end read time.
next prev parent reply other threads:[~2012-08-24 16:46 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-22 16:38 [PATCH] fs/proc: Move kfree outside pde_unload_lock Nathan Zimmer
2012-08-22 16:38 ` [PATCH] fs/prof: Update comment on pde_unload_lock Nathan Zimmer
2012-08-22 18:28 ` [PATCH] fs/proc: Move kfree outside pde_unload_lock Eric Dumazet
2012-08-22 21:42 ` Eric Dumazet
2012-08-23 17:54 ` Nathan Zimmer
2012-08-24 14:48 ` Nathan Zimmer
2012-08-24 14:58 ` Eric Dumazet
2012-08-24 16:45 ` Nathan Zimmer [this message]
2012-08-24 21:43 ` Nathan Zimmer
2012-08-28 20:38 ` Alexey Dobriyan
2012-08-29 4:11 ` Eric Dumazet
2012-08-29 8:32 ` Alexey Dobriyan
2012-08-29 13:50 ` Alexey Dobriyan
2012-08-29 14:24 ` Eric Dumazet
2012-09-17 15:57 ` Nathan Zimmer
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