Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761542AbZJMWNq (ORCPT ); Tue, 13 Oct 2009 18:13:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761532AbZJMWNp (ORCPT ); Tue, 13 Oct 2009 18:13:45 -0400 Received: from smtp-outbound-2.vmware.com ([65.115.85.73]:51299 "EHLO smtp-outbound-2.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761513AbZJMWNh (ORCPT ); Tue, 13 Oct 2009 18:13:37 -0400 Subject: Re: SCSI driver for VMware's virtual HBA - V5. From: Alok Kataria Reply-To: akataria@vmware.com To: Chris Wright Cc: James Bottomley , Randy Dunlap , Mike Christie , Bart Van Assche , "linux-scsi@vger.kernel.org" , Matthew Wilcox , "pv-drivers@vmware.com" , Roland Dreier , LKML , "Chetan.Loke@Emulex.Com" , Brian King , Rolf Eike Beer , Robert Love , Andrew Morton , Daniel Walker , Greg KH , "virtualization@lists.linux-foundataion.org" In-Reply-To: <20091013220013.GB2908@sequoia.sous-sol.org> References: <1254336812.19921.23.camel@ank32.eng.vmware.com> <20091002004725.GP3958@sequoia.sous-sol.org> <1254789028.15233.54.camel@ank32.eng.vmware.com> <20091013053726.GE17547@sequoia.sous-sol.org> <1255469294.12792.93.camel@ank32.eng.vmware.com> <20091013220013.GB2908@sequoia.sous-sol.org> Content-Type: text/plain Organization: VMware INC. Date: Tue, 13 Oct 2009 15:13:01 -0700 Message-Id: <1255471981.12792.126.camel@ank32.eng.vmware.com> Mime-Version: 1.0 X-Mailer: Evolution 2.12.3 (2.12.3-8.el5_2.3) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1419 Lines: 39 On Tue, 2009-10-13 at 15:00 -0700, Chris Wright wrote: > * Alok Kataria (akataria@vmware.com) wrote: > > On Mon, 2009-10-12 at 22:37 -0700, Chris Wright wrote: > > > > + pvscsi_template.can_queue = > > > > + min(PVSCSI_MAX_NUM_PAGES_REQ_RING, pvscsi_ring_pages) * > > > > + PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE; > > > > + pvscsi_template.cmd_per_lun = > > > > + min(pvscsi_template.can_queue, pvscsi_cmd_per_lun); > > > > > > When/how are these tunables used? Are they still useful? > > > > cmd_per_lun, is a commandline parameter. > > Actually I meant how is a user supposed to use these? They looked to me > like tunables that were part of developing a driver that may not be > needed any longer. > What are the right values, what are the tradeoffs, > etc? Or should they just be removed? The defaults are the right values, and though a normal user won't change those in practice (he can if he wants to by passing values during insmod), a developer working on performance tuning can use it. So I would like to keep these tunables around as it helps any future performance work. Thanks, Alok > > thanks, > -chris -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/