From: Shaohua Li <shli@kernel.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Wu Fengguang <wfg@linux.intel.com>,
Herbert Poetzl <herbert@13thfloor.at>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>, Jens Axboe <axboe@kernel.dk>,
Tejun Heo <tj@kernel.org>
Subject: Re: Bad SSD performance with recent kernels
Date: Mon, 30 Jan 2012 13:45:12 +0800 [thread overview]
Message-ID: <CANejiEWXDwYVtPUmOGXFxRohEmN4K3qde7z93Nw8bbk+-ZHP2w@mail.gmail.com> (raw)
In-Reply-To: <1327901519.2891.4.camel@edumazet-laptop>
2012/1/30 Eric Dumazet <eric.dumazet@gmail.com>:
> Le lundi 30 janvier 2012 à 11:17 +0800, Shaohua Li a écrit :
>
>> 1M block size is slow, I guess it's CPU related.
>>
>> And as for the big regression with newer kernel than 2.6.38, please
>> check if idle=poll
>> helps. CPU idle dramatically impacts disk performance and even latest
>> cpuidle governor
>> doesn't help for some CPUs.
>>
>
> No change with idle=poll
I mean the big regression might be related to CPU idle. because I
saw really bad performance with CPU idle with some CPUs.
The 1M block size performance is lower than 128K is not. but I still
guess it's CPU related (like copy). The test result is always like this
IIRC.
next prev parent reply other threads:[~2012-01-30 5:45 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-27 6:00 Bad SSD performance with recent kernels Herbert Poetzl
2012-01-27 6:44 ` Eric Dumazet
2012-01-28 12:51 ` Wu Fengguang
2012-01-28 13:33 ` Eric Dumazet
2012-01-29 5:59 ` Wu Fengguang
2012-01-29 8:42 ` Herbert Poetzl
2012-01-29 9:28 ` Wu Fengguang
2012-01-29 10:03 ` Eric Dumazet
2012-01-29 11:16 ` Wu Fengguang
2012-01-29 13:13 ` Eric Dumazet
2012-01-29 15:52 ` Pádraig Brady
2012-01-29 16:10 ` Wu Fengguang
2012-01-29 20:15 ` Herbert Poetzl
2012-01-30 11:18 ` Wu Fengguang
2012-01-30 12:34 ` Eric Dumazet
2012-01-30 14:01 ` Wu Fengguang
2012-01-30 14:05 ` Wu Fengguang
2012-01-30 3:17 ` Shaohua Li
2012-01-30 5:31 ` Eric Dumazet
2012-01-30 5:45 ` Shaohua Li [this message]
2012-01-30 7:13 ` Herbert Poetzl
2012-01-30 7:22 ` Shaohua Li
2012-01-30 7:36 ` Herbert Poetzl
2012-01-30 8:12 ` Shaohua Li
2012-01-30 10:31 ` Shaohua Li
2012-01-30 14:28 ` Wu Fengguang
2012-01-30 14:51 ` Eric Dumazet
2012-01-30 22:26 ` Vivek Goyal
2012-01-31 0:14 ` Shaohua Li
2012-01-31 1:07 ` Wu Fengguang
2012-01-31 3:00 ` Shaohua Li
2012-01-31 2:17 ` Eric Dumazet
2012-01-31 8:46 ` Eric Dumazet
2012-01-31 6:36 ` Herbert Poetzl
2012-01-30 14:48 ` Wu Fengguang
2012-01-28 17:01 ` Herbert Poetzl
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