From: Ilya Maximets <i.maximets@samsung.com>
To: "Michael S. Tsirkin" <mst@redhat.com>,
Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: dev@dpdk.org, tiwei.bie@intel.com, zhihong.wang@intel.com,
jasowang@redhat.com, stable@dpdk.org
Subject: Re: [dpdk-stable] [PATCH v2 0/4] vhost: add missing barriers, move prefetching
Date: Wed, 19 Dec 2018 19:28:07 +0300 [thread overview]
Message-ID: <9051b057-23df-78d4-04e0-6d02fadbd015@samsung.com> (raw)
In-Reply-To: <20181219104947-mutt-send-email-mst@kernel.org>
On 19.12.2018 18:50, Michael S. Tsirkin wrote:
> On Wed, Dec 19, 2018 at 09:21:09AM +0100, Maxime Coquelin wrote:
>> This series adds missing read barriers after reading avail index
>> for split ring and desc flags for packed ring.
>>
>> Also, it turns out that some descriptors prefetching are either
>> badly placed, or useless, last part of the series fixes that.
>>
>> With the series applied, I get between 0 and 4% gain depending
>> on the benchmark (testpmd txonly/rxonly/io).
>>
>> Thanks to Jason for reporting the missing read barriers.
>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
>
> But I wonder what effect this has on ARM where RMB isn't a NOP.
> Ilya do you happen to have any data?
Hi.
My rough testing shows no significant performance difference on ARMv8.
>
>> Changes since v1:
>> =================
>> - Drop volatile removal patch (Ilya)
>> - Improve commit messages for RMB patches (Ilya)
>>
>> Maxime Coquelin (4):
>> vhost: enforce avail index and desc read ordering
>> vhost: enforce desc flags and content read ordering
>> vhost: prefetch descriptor after the read barrier
>> vhost: remove useless prefetch for packed ring descriptor
>>
>> lib/librte_vhost/virtio_net.c | 27 ++++++++++++++++++++++-----
>> 1 file changed, 22 insertions(+), 5 deletions(-)
>>
>> --
>> 2.17.2
>
>
next prev parent reply other threads:[~2018-12-19 16:28 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-19 8:21 Maxime Coquelin
2018-12-19 8:21 ` [dpdk-stable] [PATCH v2 1/4] vhost: enforce avail index and desc read ordering Maxime Coquelin
2018-12-19 15:47 ` Michael S. Tsirkin
2018-12-19 15:50 ` Maxime Coquelin
2018-12-19 8:21 ` [dpdk-stable] [PATCH v2 2/4] vhost: enforce desc flags and content " Maxime Coquelin
2018-12-19 8:21 ` [dpdk-stable] [PATCH v2 3/4] vhost: prefetch descriptor after the read barrier Maxime Coquelin
2018-12-19 8:21 ` [dpdk-stable] [PATCH v2 4/4] vhost: remove useless prefetch for packed ring descriptor Maxime Coquelin
2018-12-19 15:49 ` Michael S. Tsirkin
2018-12-19 15:50 ` [dpdk-stable] [PATCH v2 0/4] vhost: add missing barriers, move prefetching Michael S. Tsirkin
2018-12-19 16:28 ` Ilya Maximets [this message]
2018-12-20 4:39 ` Tiwei Bie
2018-12-20 18:19 ` Maxime Coquelin
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