From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: Re: [PATCH 15/36] scsi_dh_alua: Make stpg synchronous Date: Fri, 2 Oct 2015 10:33:46 -0700 Message-ID: <560EBFFA.8010300@sandisk.com> References: <1443523658-87622-1-git-send-email-hare@suse.de> <1443523658-87622-16-git-send-email-hare@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-bn1on0073.outbound.protection.outlook.com ([157.56.110.73]:9525 "EHLO na01-bn1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753191AbbJBRdx (ORCPT ); Fri, 2 Oct 2015 13:33:53 -0400 In-Reply-To: <1443523658-87622-16-git-send-email-hare@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hannes Reinecke , James Bottomley Cc: linux-scsi@vger.kernel.org, Christoph Hellwig , Ewan Milne , "Martin K. Petersen" On 09/29/2015 03:47 AM, Hannes Reinecke wrote: > The 'activate_complete' function needs to be executed after > stpg has finished, so we can as well execute stpg synchronously > and call the function directly. Hello Hannes, Another patch in this series moves invocation of the STPG commands to the context of a workqueue. The setup on which I have been testing this patch series consists of an initiator system with four ports and a target system with eight ports and 100 LUNs. As a result, 4*8*100=3200 /dev/sd* devices are created on the initiator system and monitored by the scsi_dh_alua handler. How many kernel threads will be needed to monitor all these paths concurrently and how much memory will be required for all these kernel threads ? What if the number of LUNs would be even higher, e.g. 1000 ? Sorry but because of scalability concerns my preference is that the RTPG and STPG commands are invoked asynchronously. Thanks, Bart.