From: Vinod Koul <vinod.koul@intel.com>
To: Anup Patel <anup.patel@broadcom.com>
Cc: Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Dan Williams <dan.j.williams@intel.com>,
Florian Fainelli <f.fainelli@gmail.com>,
Scott Branden <sbranden@broadcom.com>,
Ray Jui <rjui@broadcom.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Linux ARM Kernel <linux-arm-kernel@lists.infradead.org>,
Device Tree <devicetree@vger.kernel.org>,
dmaengine@vger.kernel.org,
BCM Kernel Feedback <bcm-kernel-feedback-list@broadcom.com>
Subject: Re: [PATCH 2/6] dma: bcm-sba-raid: Peek mbox when we are left with no free requests
Date: Fri, 28 Jul 2017 08:45:01 +0530 [thread overview]
Message-ID: <20170728031500.GS3053@localhost> (raw)
In-Reply-To: <CAALAos_+ba+fg8wiqtgzWdf3L554G_jW83-J7jFoDNni5_yS9w@mail.gmail.com>
On Thu, Jul 27, 2017 at 10:25:25AM +0530, Anup Patel wrote:
> On Wed, Jul 26, 2017 at 10:40 PM, Vinod Koul <vinod.koul@intel.com> wrote:
> > On Wed, Jul 26, 2017 at 11:06:40AM +0530, Anup Patel wrote:
> >> We should peek mbox channels when we are left with no free
> >> sba_requests in sba_alloc_request()
> >
> > and why is the world should we do that, how does that help??
>
> When setting up RAID array on several NVMe disk we observed
> that sba_alloc_request() start failing (due to no free requests left)
> and RAID array setup becomes very slow.
>
> Doing mbox channel peek when we have no free requests left,
> improves performance of RAID array setup.
How about documenting this tribal knowledge in the changelog. Changelogs are
very useful, 6 months down the line, you will struggle to remember why this
was changed..
>
> This change is inspired from mv_chan_alloc_slot() implemented
> in drivers/dma/mv_xor.c
>
> Regards,
> Anup
--
~Vinod
next prev parent reply other threads:[~2017-07-28 3:15 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-26 5:36 [PATCH 0/6] Broadcom SBA-RAID driver improvements Anup Patel
2017-07-26 5:36 ` [PATCH 1/6] dma: bcm-sba-raid: Improve memory allocation in SBA RAID driver Anup Patel
[not found] ` <1501047404-14456-2-git-send-email-anup.patel-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
2017-07-26 17:09 ` Vinod Koul
2017-07-27 4:12 ` Anup Patel
[not found] ` <CAALAos_xYyvTBZB2C+tt7NvWz-4TX-mXDVJwGqhvN0FTy8QA-Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-07-28 3:13 ` Vinod Koul
2017-07-28 3:46 ` Anup Patel
2017-07-26 5:36 ` [PATCH 2/6] dma: bcm-sba-raid: Peek mbox when we are left with no free requests Anup Patel
[not found] ` <1501047404-14456-3-git-send-email-anup.patel-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
2017-07-26 17:10 ` Vinod Koul
2017-07-27 4:55 ` Anup Patel
2017-07-28 3:15 ` Vinod Koul [this message]
2017-07-28 3:39 ` Anup Patel
2017-07-26 5:36 ` [PATCH 3/6] dma: bcm-sba-raid: pre-ack async tx descriptor Anup Patel
2017-07-26 5:36 ` [PATCH 4/6] dma: bcm-sba-raid: Break sba_process_deferred_requests() into two parts Anup Patel
2017-07-26 17:15 ` Vinod Koul
2017-07-27 4:58 ` Anup Patel
2017-07-26 5:36 ` [PATCH 5/6] dma: bcm-sba-raid: Add debugfs support Anup Patel
[not found] ` <1501047404-14456-1-git-send-email-anup.patel-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
2017-07-26 5:36 ` [PATCH 6/6] arm64: dts: Add SBA-RAID DT nodes for Stingray SoC Anup Patel
2017-07-26 17:03 ` [PATCH 0/6] Broadcom SBA-RAID driver improvements Vinod Koul
2017-07-27 4:07 ` Anup Patel
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