From: Dan Williams <dan.j.williams@intel.com>
To: Johannes Thumshirn <jthumshirn@suse.de>
Cc: "Koul, Vinod" <vinod.koul@intel.com>,
"dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>
Subject: Re: [PATCH 5/5] libnvdimm: add DMA support for pmem blk-mq
Date: Fri, 4 Aug 2017 08:47:14 -0700 [thread overview]
Message-ID: <CAPcyv4jbYR87n6cLCAfK+sD+qHgSs5iEZUSK_beDsUCOVaDvMQ@mail.gmail.com> (raw)
In-Reply-To: <20170804060747.GA4218@linux-x5ow.site>
On Thu, Aug 3, 2017 at 11:07 PM, Johannes Thumshirn <jthumshirn@suse.de> wrote:
> On Thu, Aug 03, 2017 at 09:15:12AM -0700, Dan Williams wrote:
>> > I can put in a tunable knob like Johannes suggested and leave the
>> > default for that to what it is currently. And we can adjust as necessary
>> > as we do more testing.
>>
>> That's the problem, we need a multi-dimensional knob. It's not just
>> transfer-size that effects total delivered bandwidth.
>
> If Dan opposes it so much, I'm OK with no tunable. I'm just expressing my
> concern that we get reports like this [1] one here as a result.
Sorry if I came off harsh. In that report from Mel he's showing a slow
down in a representative workload not just a canned bandwidth
benchmark. I'm worried that tuning for a single dimension on an fio
run doesn't actually improve throughput delivered to an application.
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next prev parent reply other threads:[~2017-08-04 15:45 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-31 22:24 [PATCH 0/5] Adding blk-mq and DMA support to pmem block driver Dave Jiang
2017-07-31 22:24 ` [PATCH 1/5] dmaengine: ioatdma: revert 7618d035 to allow sharing of DMA channels Dave Jiang
2017-07-31 22:24 ` [PATCH 2/5] dmaengine: ioatdma: dma_prep_memcpy_to/from_sg support Dave Jiang
2017-08-01 2:14 ` Dan Williams
2017-08-01 16:39 ` Dave Jiang
2017-08-02 4:57 ` Vinod Koul
2017-07-31 22:24 ` [PATCH 3/5] dmaengine: add SG support to dmaengine_unmap Dave Jiang
2017-07-31 22:24 ` [PATCH 4/5] libnvdimm: Adding blk-mq support to the pmem driver Dave Jiang
2017-08-01 19:02 ` Ross Zwisler
2017-07-31 22:24 ` [PATCH 5/5] libnvdimm: add DMA support for pmem blk-mq Dave Jiang
2017-08-01 7:34 ` Johannes Thumshirn
2017-08-01 16:40 ` Dave Jiang
2017-08-01 17:43 ` Dan Williams
2017-08-03 8:06 ` Johannes Thumshirn
2017-08-03 15:41 ` Dan Williams
2017-08-03 16:12 ` Dave Jiang
2017-08-03 16:15 ` Dan Williams
2017-08-04 6:07 ` Johannes Thumshirn
2017-08-04 15:47 ` Dan Williams [this message]
2017-08-01 20:42 ` Ross Zwisler
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