Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933598AbZDCRJA (ORCPT ); Fri, 3 Apr 2009 13:09:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932505AbZDCRIq (ORCPT ); Fri, 3 Apr 2009 13:08:46 -0400 Received: from mail-bw0-f169.google.com ([209.85.218.169]:53681 "EHLO mail-bw0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932287AbZDCRIo (ORCPT ); Fri, 3 Apr 2009 13:08:44 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=hfTVGdGNSXPxa+kh6fbBw/W53yNzAxI17eR4rJqBn1+lk0HmCyyXFNkrp3Upc8VJbi +AQDlMC+Sf0k4bWtT2CCV7f6WyrZzuEvhA8JLRO6vOW/TFBOcHMhBV4eDnBH57mlWOkx 7uiv7C6NM5SY/3HgzVHMQRFKC/KdnuMMbwYgY= MIME-Version: 1.0 In-Reply-To: <49D4F2E1.7000507@vlnb.net> References: <49D10256.8030307@vlnb.net> <49D4F2E1.7000507@vlnb.net> Date: Fri, 3 Apr 2009 19:08:41 +0200 Message-ID: Subject: Re: [Scst-devel] ISCSI-SCST performance (with also IET and STGT data) From: Bart Van Assche To: Vladislav Bolkhovitin Cc: scst-devel , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1406 Lines: 32 On Thu, Apr 2, 2009 at 7:16 PM, Vladislav Bolkhovitin wrote: > Bart Van Assche, on 04/02/2009 12:14 AM wrote: >> I have repeated some of these performance tests for iSCSI over IPoIB >> (two DDR PCIe 1.0 ConnectX HCA's connected back to back). The results >> for the buffered I/O test with a block size of 512K (initiator) >> against a file of 1GB residing on a tmpfs filesystem on the target are >> as follows: >> >> write-test: iSCSI-SCST 243 MB/s; IET 192 MB/s. >> read-test: iSCSI-SCST 291 MB/s; IET 223 MB/s. >> >> And for a block size of 4 KB: >> >> write-test: iSCSI-SCST 43 MB/s; IET 42 MB/s. >> read-test: iSCSI-SCST 288 MB/s; IET 221 MB/s. > > Do you have any thoughts why writes are so bad? It shouldn't be so.. It's not impossible that with the 4 KB write test I hit the limits of the initiator system (Intel E6750 CPU, 2.66 GHz, two cores). Some statistics I gathered during the 4 KB write test: Target: CPU load 0.5, 16500 mlx4-comp-0 interrupts per second, same number of interrupts processed by each core (8250/s). Initiator: CPU load 1.0, 32850 mlx4-comp-0 interrupts per second, all interrupts occurred on the same core. Bart. -- 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/