DPDK patches and discussions
 help / color / mirror / Atom feed
From: Thomas Monjalon <thomas@monjalon.net>
To: Cheng Jiang <Cheng1.jiang@intel.com>,
	Maxime Coquelin <maxime.coquelin@redhat.com>,
	bruce.richardson@intel.com
Cc: chenbo.xia@intel.com, dev@dpdk.org, jiayu.hu@intel.com,
	yvonnex.yang@intel.com, yinan.wang@intel.com, alexr@nvidia.com,
	shahafs@nvidia.com
Subject: Re: [dpdk-dev] [PATCH] examples/vhost: fix ioat ring space in callbacks
Date: Wed, 07 Apr 2021 10:26:12 +0200	[thread overview]
Message-ID: <2267082.chWHW8dCnR@thomas> (raw)
In-Reply-To: <23c4f6e7-4895-44b7-4ff0-3a02f9f3f86a@redhat.com>

07/04/2021 09:47, Maxime Coquelin:
> 
> On 3/17/21 6:40 AM, Cheng Jiang wrote:
> > We use ioat ring space for determining if ioat callbacks can enqueue a
> > packet to ioat device. But there is one slot can't be used in ioat
> > ring due to the ioat driver design, so we need to reduce one slot in
> > ioat ring to prevent ring size mismatch in ioat callbacks.
> > 
> > Fixes: 2aa47e94bfb2 ("examples/vhost: add ioat ring space count and check")
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Cheng Jiang <Cheng1.jiang@intel.com>
> > ---
> >  examples/vhost/ioat.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/examples/vhost/ioat.c b/examples/vhost/ioat.c
> > index 60b73be93..9cb5e0d50 100644
> > --- a/examples/vhost/ioat.c
> > +++ b/examples/vhost/ioat.c
> > @@ -113,7 +113,7 @@ open_ioat(const char *value)
> >  			goto out;
> >  		}
> >  		rte_rawdev_start(dev_id);
> > -		cb_tracker[dev_id].ioat_space = IOAT_RING_SIZE;
> > +		cb_tracker[dev_id].ioat_space = IOAT_RING_SIZE - 1;
> 
> That really comforts me in thinking we need a generic abstraction for
> DMA devices. How is the application developer supposed to know that
> the DMA driver has such weird limitations?

Having a generic DMA API may be interesting.
Do you know any other HW candidate for such an API?
Do you think rte_memcpy can be used as a SW driver?



  parent reply	other threads:[~2021-04-07  8:26 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-17  5:40 Cheng Jiang
2021-03-17  6:58 ` Hu, Jiayu
2021-04-07  7:47 ` Maxime Coquelin
2021-04-07  7:54   ` Hu, Jiayu
2021-04-13  8:50     ` Maxime Coquelin
2021-04-13  9:55       ` Jiang, Cheng1
2021-04-07  8:26   ` Thomas Monjalon [this message]
2021-04-07  8:43     ` Thomas Monjalon
2021-04-18 15:10       ` Liang Ma
2021-04-07  8:48     ` Maxime Coquelin
2021-04-28  2:09 ` Xia, Chenbo

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=2267082.chWHW8dCnR@thomas \
    --to=thomas@monjalon.net \
    --cc=Cheng1.jiang@intel.com \
    --cc=alexr@nvidia.com \
    --cc=bruce.richardson@intel.com \
    --cc=chenbo.xia@intel.com \
    --cc=dev@dpdk.org \
    --cc=jiayu.hu@intel.com \
    --cc=maxime.coquelin@redhat.com \
    --cc=shahafs@nvidia.com \
    --cc=yinan.wang@intel.com \
    --cc=yvonnex.yang@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).