From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladislav Bolkhovitin Subject: Re: [Scst-devel] New qla2x00tgt Driver Question Date: Thu, 04 Dec 2014 20:05:05 -0800 Message-ID: <54812EF1.9030701@vlnb.net> References: <201412040742.sB47gbGX032229@wind.enjellic.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mout.kundenserver.de ([212.227.17.24]:56253 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933316AbaLEEFQ (ORCPT ); Thu, 4 Dec 2014 23:05:16 -0500 In-Reply-To: <201412040742.sB47gbGX032229@wind.enjellic.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: greg@enjellic.com, Duane Grigsby , Marc Smith , scst-devel Cc: linux-scsi Dr. Greg Wettstein wrote on 12/03/2014 11:42 PM: > On Dec 3, 8:59pm, Vladislav Bolkhovitin wrote: > } Subject: Re: [Scst-devel] New qla2x00tgt Driver Question > >> Dr. Greg Wettstein wrote on 12/03/2014 12:46 PM: >>> Secondly, Vlad, we have been running additional testing for the last >>> two days and we have logs from the SCST core which I am including >>> below which suggests that the SCST core target code excessively stalls >>> or mishandles an ABORT while processing a NEXUS_LOSS_SESS TMF. >>> Regardless of your feelings about the target driver code in the kernel >>> we need to make sure there is not some subtle regression in the core >>> SCST code paths during TMF processing. >> >> I don't see any problem on the SCST core level in the logs. > > Fair enough, thanks for taking a look. > > I though it was somewhat strange to see deferred ABORT's on I/O being > done to RAM based block devices as there is little or no I/O latency. > In our testing, this regression always occurs on TMF function 6 > processing and this was also the case in Marc's report. The comment > that one of the other posters made that this was secondary to slow > backstorage didn't match the characteristics of our test environment. For TM processing backend and frontend (target) sides are equal, so the longest side processing is what that defines your TM processing time. Vlad