[dpdk-dev] Process question: reviewing older patches

[Jay Rolette]

Thanks Thomas and Neil. Sadly, no joy. While I generally like gmail for my
mail, there's not a reasonable way to import the mbox file or to control
the message id.

If someone else wants to resend the message to the list, I can reply to
that. Otherwise, here are the relevant bits from the original patch email:

>From patchwork Wed Jul 23 06:45:12 2014
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Subject: [dpdk-dev] kni: optimizing the rte_kni_rx_burst
From: Hemant Agrawal <Hemant at freescale.com>
X-Patchwork-Id: 84
Message-Id: <14060979121185-git-send-email-Hemant at freescale.com>
To: <dev at dpdk.org>
Date: Wed, 23 Jul 2014 12:15:12 +0530

The current implementation of rte_kni_rx_burst polls the fifo for buffers.
Irrespective of success or failure, it allocates the mbuf and try to put
them into the alloc_q
if the buffers are not added to alloc_q, it frees them.
This waste lots of cpu cycles in allocating and freeing the buffers if
alloc_q is full.

The logic has been changed to:
1. Initially allocand add buffer(burstsize) to alloc_q
2. Add buffers to alloc_q only when you are pulling out the buffers.

Signed-off-by: Hemant Agrawal <Hemant at freescale.com>

---
lib/librte_kni/rte_kni.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/librte_kni/rte_kni.c b/lib/librte_kni/rte_kni.c
index 76feef4..01e85f8 100644
--- a/lib/librte_kni/rte_kni.c
+++ b/lib/librte_kni/rte_kni.c
@@ -263,6 +263,9 @@ rte_kni_alloc(struct rte_mempool *pktmbuf_pool,

  ctx->in_use = 1;

+ /* Allocate mbufs and then put them into alloc_q */
+ kni_allocate_mbufs(ctx);
+
  return ctx;

 fail:
@@ -369,8 +372,9 @@ rte_kni_rx_burst(struct rte_kni *kni, struct rte_mbuf
**mbufs, unsigned num)
 {
  unsigned ret = kni_fifo_get(kni->tx_q, (void **)mbufs, num);

- /* Allocate mbufs and then put them into alloc_q */
- kni_allocate_mbufs(kni);
+ /* If buffers removed, allocate mbufs and then put them into alloc_q */
+ if(ret)
+ kni_allocate_mbufs(kni);

  return ret;
 }

The patch looks good from a DPDK 1.6r2 viewpoint. We saw the same behavior
in our app and ended up avoiding it higher in the stack (in our code).

Reviewed-by: Jay Rolette <rolette at infiniteio.com>

Jay

On Wed, Jan 28, 2015 at 10:49 AM, Neil Horman <nhorman at tuxdriver.com> wrote:

> On Wed, Jan 28, 2015 at 09:52:48AM -0600, Jay Rolette wrote:
> > There's a fairly old KNI patch (http://dpdk.org/dev/patchwork/patch/84/)
> > that I reviewed, but I'm not seeing how to submit my "Reviewed-by" when I
> > don't have any of the emails from the patch in my mail client.
> >
> > I can copy the text from the 'mbox' link in Patchwork into an email, but
> > I'm guessing that may not make the patch toolchain happy.
> >
> > What's the right way to do this?
> >
> Just grab the message id from the patchwork site, and list it in the
> envelope
> headers in-reply-to: field when you respond.  You won't have the rest of
> the
> conversation field in the thread, but you will respond properly to the
> thread,
> and patchwork will pick up the ACK
> Neil
>
> > Thanks,
> > Jay
> >
>