From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: SMP-aware kcryptd? Date: Mon, 13 Apr 2009 15:41:33 +0200 Message-ID: <49E3410D.9040500@wpkg.org> Reply-To: dm-crypt-4q3lyFh4P1g@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: List-Post: List-Help: List-Unsubscribe: List-Subscribe: To: dm-crypt-4q3lyFh4P1g@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org List-Id: dm-devel.ids Currently, the trend with CPUs is to add more cores rather than increase the speed of a single core. This does not scale very well with certain things in the Linux kernel. One of them is kcryptd. A system able to deliver data with a speed of ~200 MB/s from a RAID array, will be only able to deliver a fraction of it (i.e. ~40 MB/s in my case) when reads are being done from a dm-crypt device. This is because kcryptd is not SMP-aware: it performs all calculations on a single logical CPU only. Are there any plans to change it? -- Tomasz Chmielewski http://wpkg.org