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From: Hannes Reinecke <hare@suse.de>
To: Tyrel Datwyler <tyreld@linux.ibm.com>,
	james.bottomley@hansenpartnership.com
Cc: martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	brking@linux.ibm.com
Subject: Re: [PATCH 00/13] ibmvfc: initial MQ development
Date: Wed, 2 Dec 2020 13:03:18 +0100	[thread overview]
Message-ID: <90e9a8ac-d2b9-bb64-7c7d-607adaea0f26@suse.de> (raw)
In-Reply-To: <20201126014824.123831-1-tyreld@linux.ibm.com>

On 11/26/20 2:48 AM, Tyrel Datwyler wrote:
> Recent updates in pHyp Firmware and VIOS releases provide new infrastructure
> towards enabling Subordinate Command Response Queues (Sub-CRQs) such that each
> Sub-CRQ is a channel backed by an actual hardware queue in the FC stack on the
> partner VIOS. Sub-CRQs are registered with the firmware via hypercalls and then
> negotiated with the VIOS via new Management Datagrams (MADs) for channel setup.
> 
> This initial implementation adds the necessary Sub-CRQ framework and implements
> the new MADs for negotiating and assigning a set of Sub-CRQs to associated VIOS
> HW backed channels. The event pool and locking still leverages the legacy single
> queue implementation, and as such lock contention is problematic when increasing
> the number of queues. However, this initial work demonstrates a 1.2x factor
> increase in IOPs when configured with two HW queues despite lock contention.
> 
Why do you still hold the hold lock during submission?
An initial check on the submission code path didn't reveal anything 
obvious, so it _should_ be possible to drop the host lock there.
Or at least move it into the submission function itself to avoid lock 
contention. Hmm?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

  parent reply	other threads:[~2020-12-02 12:04 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-26  1:48 [PATCH 00/13] ibmvfc: initial MQ development Tyrel Datwyler
2020-11-26  1:48 ` [PATCH 01/13] ibmvfc: add vhost fields and defaults for MQ enablement Tyrel Datwyler
2020-11-27 17:45   ` Brian King
2020-11-30 17:22     ` Tyrel Datwyler
2020-11-26  1:48 ` [PATCH 02/13] ibmvfc: define hcall wrapper for registering a Sub-CRQ Tyrel Datwyler
2020-11-27 17:45   ` Brian King
2020-11-26  1:48 ` [PATCH 03/13] ibmvfc: add Subordinate CRQ definitions Tyrel Datwyler
2020-11-27 17:46   ` Brian King
2020-11-26  1:48 ` [PATCH 04/13] ibmvfc: add alloc/dealloc routines for SCSI Sub-CRQ Channels Tyrel Datwyler
2020-11-27 17:46   ` Brian King
2020-11-30 17:26     ` Tyrel Datwyler
2020-11-26  1:48 ` [PATCH 05/13] ibmvfc: add Sub-CRQ IRQ enable/disable routine Tyrel Datwyler
2020-11-27 17:47   ` Brian King
2020-11-26  1:48 ` [PATCH 06/13] ibmvfc: add handlers to drain and complete Sub-CRQ responses Tyrel Datwyler
2020-11-27 17:47   ` Brian King
2020-11-30 17:27     ` Tyrel Datwyler
2020-11-26  1:48 ` [PATCH 07/13] ibmvfc: define Sub-CRQ interrupt handler routine Tyrel Datwyler
2020-11-27 17:48   ` Brian King
2020-11-26  1:48 ` [PATCH 08/13] ibmvfc: map/request irq and register Sub-CRQ interrupt handler Tyrel Datwyler
2020-11-27 17:48   ` Brian King
2020-11-26  1:48 ` [PATCH 09/13] ibmvfc: implement channel enquiry and setup commands Tyrel Datwyler
2020-11-27 17:49   ` Brian King
2020-11-30 17:29     ` Tyrel Datwyler
2020-11-26  1:48 ` [PATCH 10/13] ibmvfc: advertise client support for using hardware channels Tyrel Datwyler
2020-11-27 17:49   ` Brian King
2020-11-26  1:48 ` [PATCH 11/13] ibmvfc: set and track hw queue in ibmvfc_event struct Tyrel Datwyler
2020-11-27 17:50   ` Brian King
2020-11-26  1:48 ` [PATCH 12/13] ibmvfc: send commands down HW Sub-CRQ when channelized Tyrel Datwyler
2020-11-27 17:50   ` Brian King
2020-11-26  1:48 ` [PATCH 13/13] ibmvfc: register Sub-CRQ handles with VIOS during channel setup Tyrel Datwyler
2020-11-27 17:50   ` Brian King
2020-12-02 12:03 ` Hannes Reinecke [this message]
2020-12-02 17:19   ` [PATCH 00/13] ibmvfc: initial MQ development Tyrel Datwyler

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