Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 1 Jan 2002 20:01:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 1 Jan 2002 20:00:51 -0500 Received: from SMTP7.ANDREW.CMU.EDU ([128.2.10.87]:52242 "EHLO smtp7.andrew.cmu.edu") by vger.kernel.org with ESMTP id ; Tue, 1 Jan 2002 20:00:44 -0500 Date: Tue, 1 Jan 2002 20:00:43 -0500 (EST) From: Steinar Hauan X-X-Sender: To: Subject: smp cputime issues Message-ID: MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="-559023410-851401618-1009933243=:7513" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. Send mail to mime@docserver.cac.washington.edu for more info. ---559023410-851401618-1009933243=:7513 Content-Type: TEXT/PLAIN; charset=US-ASCII hello, we are encountering some weird timing behaviour on our linux cluster. specifically: when running 2 copies of selected programs on a dual-cpu system, the cputime reported for each process is up to 25% higher than when the processes are run on their own. however, if running two different jobs on the same machine, both complete with a cputime equal to when run individually. sample timing output attached. profiling confirms that everything slows down approximately to scale. the results reproduce on a range of different machines (see below). additional specifications: - kernel version 2.4.16 (with apic enabled) - chipsets: apollo pro 133, apollo pro 266, intel i860, serverworks LE - all jobs requires less than 1/10 of physical memory - no significant disk i/o takes place - timing with dtime(), /usr/bin/time and shell built-in time - this behavior is NOT seen for all applications. the worst "offender" spends most of its time doing linear algebra. ideas or info-pointers appreciated. more specs available on request. regards, -- Steinar Hauan, dept of ChemE -- hauan@cmu.edu Carnegie Mellon University, Pittsburgh PA, USA ---559023410-851401618-1009933243=:7513 Content-Type: TEXT/PLAIN; charset=US-ASCII; name="one.txt" Content-Transfer-Encoding: BASE64 Content-ID: Content-Description: Content-Disposition: attachment; filename="one.txt" b3V0cHV0IGZyb20gcnVubmluZyBhIHNpbmdsZSBpbWFnZSBjb3B5DQoNClty ZXBvcnRlZCBieSBkdGltZSgpXQ0KDQpDUFUgc2Vjb25kcyBzcGVudCBpbiBJ UE9QVCBhbmQgZnVuY3Rpb24gZXZhbHVhdGlvbnMgPSAgICAgMTMxLjk5OTk5 ODINCg0KW3JlcG9ydGVkIGJ5IC91c3IvYmluL3RpbWUgLXYgXQ0KDQoJQ29t bWFuZCBiZWluZyB0aW1lZDogIi4vaXBvcHQgcm9ib3RfMjAwMC5ubCINCglV c2VyIHRpbWUgKHNlY29uZHMpOiAxMzQuMDENCglTeXN0ZW0gdGltZSAoc2Vj b25kcyk6IDAuMzYNCglQZXJjZW50IG9mIENQVSB0aGlzIGpvYiBnb3Q6IDk5 JQ0KCUVsYXBzZWQgKHdhbGwgY2xvY2spIHRpbWUgKGg6bW06c3Mgb3IgbTpz cyk6IDI6MTQuNDINCglBdmVyYWdlIHNoYXJlZCB0ZXh0IHNpemUgKGtieXRl cyk6IDANCglBdmVyYWdlIHVuc2hhcmVkIGRhdGEgc2l6ZSAoa2J5dGVzKTog MA0KCUF2ZXJhZ2Ugc3RhY2sgc2l6ZSAoa2J5dGVzKTogMA0KCUF2ZXJhZ2Ug dG90YWwgc2l6ZSAoa2J5dGVzKTogMA0KCU1heGltdW0gcmVzaWRlbnQgc2V0 IHNpemUgKGtieXRlcyk6IDANCglBdmVyYWdlIHJlc2lkZW50IHNldCBzaXpl IChrYnl0ZXMpOiAwDQoJTWFqb3IgKHJlcXVpcmluZyBJL08pIHBhZ2UgZmF1 bHRzOiAyOTMNCglNaW5vciAocmVjbGFpbWluZyBhIGZyYW1lKSBwYWdlIGZh dWx0czogMjMzNTINCglWb2x1bnRhcnkgY29udGV4dCBzd2l0Y2hlczogMA0K CUludm9sdW50YXJ5IGNvbnRleHQgc3dpdGNoZXM6IDANCglTd2FwczogMA0K CUZpbGUgc3lzdGVtIGlucHV0czogMA0KCUZpbGUgc3lzdGVtIG91dHB1dHM6 IDANCglTb2NrZXQgbWVzc2FnZXMgc2VudDogMA0KCVNvY2tldCBtZXNzYWdl cyByZWNlaXZlZDogMA0KCVNpZ25hbHMgZGVsaXZlcmVkOiAwDQoJUGFnZSBz aXplIChieXRlcyk6IDQwOTYNCglFeGl0IHN0YXR1czogMA0K ---559023410-851401618-1009933243=:7513 Content-Type: TEXT/PLAIN; charset=US-ASCII; name="two.txt" Content-Transfer-Encoding: BASE64 Content-ID: Content-Description: Content-Disposition: attachment; filename="two.txt" b3V0cHV0IGZyb20gcnVubmluZyB0d28gaW1hZ2VzIHNpbXVsdGFuZW91c2x5 DQoNCltyZXBvcnRlZCBieSBkdGltZSgpXQ0KDQpDUFUgc2Vjb25kcyBzcGVu dCBpbiBJUE9QVCBhbmQgZnVuY3Rpb24gZXZhbHVhdGlvbnMgPSAgICAgMTU3 LjcwMDAwMjQNCg0KW3JlcG9ydGVkIGJ5IC91c3IvYmluL3RpbWUgLXYgXQ0K CUNvbW1hbmQgYmVpbmcgdGltZWQ6ICIuL2lwb3B0IHJvYm90XzIwMDAubmwi DQoJVXNlciB0aW1lIChzZWNvbmRzKTogMTU5LjgxDQoJU3lzdGVtIHRpbWUg KHNlY29uZHMpOiAwLjUwDQoJUGVyY2VudCBvZiBDUFUgdGhpcyBqb2IgZ290 OiA5OSUNCglFbGFwc2VkICh3YWxsIGNsb2NrKSB0aW1lIChoOm1tOnNzIG9y IG06c3MpOiAyOjQwLjQxDQoJQXZlcmFnZSBzaGFyZWQgdGV4dCBzaXplIChr Ynl0ZXMpOiAwDQoJQXZlcmFnZSB1bnNoYXJlZCBkYXRhIHNpemUgKGtieXRl cyk6IDANCglBdmVyYWdlIHN0YWNrIHNpemUgKGtieXRlcyk6IDANCglBdmVy YWdlIHRvdGFsIHNpemUgKGtieXRlcyk6IDANCglNYXhpbXVtIHJlc2lkZW50 IHNldCBzaXplIChrYnl0ZXMpOiAwDQoJQXZlcmFnZSByZXNpZGVudCBzZXQg c2l6ZSAoa2J5dGVzKTogMA0KCU1ham9yIChyZXF1aXJpbmcgSS9PKSBwYWdl IGZhdWx0czogMjkzDQoJTWlub3IgKHJlY2xhaW1pbmcgYSBmcmFtZSkgcGFn ZSBmYXVsdHM6IDIzMzUyDQoJVm9sdW50YXJ5IGNvbnRleHQgc3dpdGNoZXM6 IDANCglJbnZvbHVudGFyeSBjb250ZXh0IHN3aXRjaGVzOiAwDQoJU3dhcHM6 IDANCglGaWxlIHN5c3RlbSBpbnB1dHM6IDANCglGaWxlIHN5c3RlbSBvdXRw dXRzOiAwDQoJU29ja2V0IG1lc3NhZ2VzIHNlbnQ6IDANCglTb2NrZXQgbWVz c2FnZXMgcmVjZWl2ZWQ6IDANCglTaWduYWxzIGRlbGl2ZXJlZDogMA0KCVBh Z2Ugc2l6ZSAoYnl0ZXMpOiA0MDk2DQoJRXhpdCBzdGF0dXM6IDANCg== ---559023410-851401618-1009933243=:7513-- - 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/