Hi Alexei,
On 07/09/2016 8:31 PM, Alexei Starovoitov wrote:
On Wed, Sep 07, 2016 at 03:42:22PM +0300, Saeed Mahameed wrote:
From: Tariq Toukan <tar...@mellanox.com>
To improve the memory consumption scheme, we omit the flow that
demands and splits high-order pages in Striding RQ, and stay
with a single Striding RQ flow that uses order-0 pages.
Moving to fragmented memory allows the use of larger MPWQEs,
which reduces the number of UMR posts and filler CQEs.
Moving to a single flow allows several optimizations that improve
performance, especially in production servers where we would
anyway fallback to order-0 allocations:
- inline functions that were called via function pointers.
- improve the UMR post process.
This patch alone is expected to give a slight performance reduction.
However, the new memory scheme gives the possibility to use a page-cache
of a fair size, that doesn't inflate the memory footprint, which will
dramatically fix the reduction and even give a huge gain.
We ran pktgen single-stream benchmarks, with iptables-raw-drop:
Single stride, 64 bytes:
* 4,739,057 - baseline
* 4,749,550 - this patch
no reduction
Larger packets, no page cross, 1024 bytes:
* 3,982,361 - baseline
* 3,845,682 - this patch
3.5% reduction
Larger packets, every 3rd packet crosses a page, 1500 bytes:
* 3,731,189 - baseline
* 3,579,414 - this patch
4% reduction
imo it's not a realistic use case, but would be good to mention that
patch 3 brings performance back for this use case anyway.
Exactly, that's what I meant in the previous paragraph (".. will
dramatically fix the reduction and even give a huge gain.")
Regards,
Tariq
