|author||Yongseok Koh <email@example.com>||2019-04-01 14:17:54 -0700|
|committer||Ferruh Yigit <firstname.lastname@example.org>||2019-04-05 17:45:22 +0200|
net/mlx5: add control of excessive memory pinning by kernel
A new PMD parameter (mr_ext_memseg_en) is added to control extension of memseg when creating a MR. It is enabled by default. If enabled, mlx5_mr_create() tries to maximize the range of MR registration so that the LKey lookup tables on datapath become smaller and get the best performance. However, it may worsen memory utilization because registered memory is pinned by kernel driver. Even if a page in the extended chunk is freed, that doesn't become reusable until the entire memory is freed and the MR is destroyed. To make freed pages available immediately, this parameter has to be turned off but it could drop performance. Signed-off-by: Yongseok Koh <email@example.com> Acked-by: Shahaf Shuler <firstname.lastname@example.org>
Diffstat (limited to 'doc/guides/nics/mlx5.rst')
1 files changed, 11 insertions, 0 deletions
diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst
index fa9bf73..e5e3d90 100644
@@ -485,6 +485,17 @@ Run-time configuration
Disabled by default.
+- ``mr_ext_memseg_en`` parameter [int]
+ A nonzero value enables extending memseg when registering DMA memory. If
+ enabled, the number of entries in MR (Memory Region) lookup table on datapath
+ is minimized and it benefits performance. On the other hand, it worsens memory
+ utilization because registered memory is pinned by kernel driver. Even if a
+ page in the extended chunk is freed, that doesn't become reusable until the
+ entire memory is freed.
+ Enabled by default.
- ``representor`` parameter [list]
This parameter can be used to instantiate DPDK Ethernet devices from