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From: Roland Dreier <rdreier@cisco.com>
To: Shirley Ma <xma@us.ibm.com>
Cc: linux-kernel@vger.kernel.org, openib-general@openib.org,
	linuxppc-dev@ozlabs.org, Christoph Raisch <RAISCH@de.ibm.com>,
	Hoang-Nam Nguyen <HNGUYEN@de.ibm.com>,
	Marcus Eder <MEDER@de.ibm.com>,
	openib-general-bounces@openib.org,
	"Michael S. Tsirkin" <mst@mellanox.co.il>
Subject: Re: [openib-general] Re: [PATCH 07/16] ehca: interrupt handling routines
Date: Tue, 09 May 2006 11:36:07 -0700	[thread overview]
Message-ID: <adar733avvs.fsf@cisco.com> (raw)
In-Reply-To: <OF22D08323.20D303C1-ON87257169.0063C980-88257169.006A41AB@us.ibm.com> (Shirley Ma's message of "Tue, 9 May 2006 11:27:29 -0700")

    Shirley> I have done some patch like that on top of splitting
    Shirley> CQ. The problem I found that hardware interrupt favors
    Shirley> one CPU. Most of the time these two threads are running
    Shirley> on the same cpu according to my debug output. You can
    Shirley> easily find out by cat /proc/interrupts and
    Shirley> /proc/irq/XXX/smp_affinity.  ehca has distributed
    Shirley> interrupts evenly on SMP, so it gets the benefits of two
    Shirley> threads, and gains much better throughputs.

Yes, an interrupt will likely be delivered to one CPU.

But there's no reason why the two threads can't be pinned to different
CPUs or given exclusive CPU masks, exactly the same way that ehca
implements it.

 - R.

WARNING: multiple messages have this Message-ID (diff)
From: Roland Dreier <rdreier@cisco.com>
To: Shirley Ma <xma@us.ibm.com>
Cc: "Michael S. Tsirkin" <mst@mellanox.co.il>,
	linux-kernel@vger.kernel.org, openib-general@openib.org,
	linuxppc-dev@ozlabs.org, Christoph Raisch <RAISCH@de.ibm.com>,
	Hoang-Nam Nguyen <HNGUYEN@de.ibm.com>,
	Marcus Eder <MEDER@de.ibm.com>,
	openib-general-bounces@openib.org
Subject: Re: [openib-general] Re: [PATCH 07/16] ehca: interrupt handling routines
Date: Tue, 09 May 2006 11:36:07 -0700	[thread overview]
Message-ID: <adar733avvs.fsf@cisco.com> (raw)
In-Reply-To: <OF22D08323.20D303C1-ON87257169.0063C980-88257169.006A41AB@us.ibm.com> (Shirley Ma's message of "Tue, 9 May 2006 11:27:29 -0700")

    Shirley> I have done some patch like that on top of splitting
    Shirley> CQ. The problem I found that hardware interrupt favors
    Shirley> one CPU. Most of the time these two threads are running
    Shirley> on the same cpu according to my debug output. You can
    Shirley> easily find out by cat /proc/interrupts and
    Shirley> /proc/irq/XXX/smp_affinity.  ehca has distributed
    Shirley> interrupts evenly on SMP, so it gets the benefits of two
    Shirley> threads, and gains much better throughputs.

Yes, an interrupt will likely be delivered to one CPU.

But there's no reason why the two threads can't be pinned to different
CPUs or given exclusive CPU masks, exactly the same way that ehca
implements it.

 - R.

  reply	other threads:[~2006-05-09 18:36 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-04-27 10:48 [PATCH 07/16] ehca: interrupt handling routines Heiko J Schick
2006-05-04 21:29 ` [openib-general] " Roland Dreier
2006-05-04 21:29   ` Roland Dreier
2006-05-05 13:05   ` Heiko J Schick
2006-05-05 13:05     ` Heiko J Schick
2006-05-05 14:49     ` Roland Dreier
2006-05-09 12:35       ` Heiko J Schick
2006-05-09 16:23         ` Roland Dreier
2006-05-09 16:49           ` Michael S. Tsirkin
2006-05-09 16:49             ` Michael S. Tsirkin
2006-05-09 18:27             ` [openib-general] " Shirley Ma
2006-05-09 18:36               ` Roland Dreier [this message]
2006-05-09 18:36                 ` Roland Dreier
2006-05-09 18:44                 ` Shirley Ma
2006-05-09 18:44               ` Michael S. Tsirkin
2006-05-09 18:44                 ` Michael S. Tsirkin
2006-05-09 18:51                 ` Shirley Ma
2006-05-09 18:55                   ` Michael S. Tsirkin
2006-05-09 18:55                     ` Michael S. Tsirkin
2006-05-09 18:57             ` [openib-general] " Heiko J Schick
2006-05-09 19:04               ` Stephen Hemminger
2006-05-09 19:46               ` Shirley Ma
2006-05-09 20:20                 ` Michael S. Tsirkin
2006-05-09 20:20                   ` Michael S. Tsirkin
2006-05-09 21:28                   ` Shirley Ma
2006-05-10  5:33                     ` Michael S. Tsirkin
2006-05-10  5:33                       ` Michael S. Tsirkin
2006-05-09 23:35           ` [openib-general] " Segher Boessenkool
2006-05-09 23:35             ` Segher Boessenkool
2006-05-09 13:15 ` Christoph Hellwig
2006-05-09 13:15   ` Christoph Hellwig

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