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authorGary S. Robertson <gary.robertson@linaro.org>2015-08-20 00:04:57 -0500
committerGary S. Robertson <gary.robertson@linaro.org>2015-08-20 13:37:37 -0500
commit5eaa873c704ea6de30fe6271214f3f3138252a01 (patch)
tree1d89909b6c7819375c7817d05f5ab1f6d44e9aa1
parent722e9208f75d0fecf2faca98c2fda65b05ca1fc1 (diff)
README: Update for the 2015.08 release2015.08
Signed-off-by: Gary S. Robertson <gary.robertson@linaro.org>
-rw-r--r--README.textile26
1 files changed, 16 insertions, 10 deletions
diff --git a/README.textile b/README.textile
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@@ -1,18 +1,21 @@
p. The Linaro Networking Group (LNG) is pleased to announce the
-2015.07 release of the Linaro Networking Kernel.
+2015.08 release of the Linaro Networking Kernel.
h4. Interesting changes include:
-* The LNG v3.14 kernel branches have been updated with the June 2015 releases of the respective Linaro Stable Kernel (LSK) v3.14 branches.
-* The LNG v3.18 kernel branches have been updated with the June 2015 releases of the respective LSK v3.18 branches.
-* The latest available NOHZ_FULL isolation patches have been forward-ported from the LNG 3.14 branches to the LNG v3.18 branches.
+* The LNG v3.14 kernel branches have been superseded by the LNG v3.18 branches and are no longer being updated.
+* The LNG v3.18 kernel branches have been updated with the July 2015 releases of the respective LSK v3.18 branches.
+* Both LNG v3.18 branches are now capable of achieving extended periods of full tickless (i.e. NO_HZ_FULL) isolation when given the proper initialization.
+* Two new LNG v4.1 branches have been added, since the RT patch set is now available for the 4.1 kernel.
+* The new LNG v4.1 branches are based on corresponding LSK v4.1 branches, but with patches added to enhance NO_HZ_FULL capabilities.
+* The linux-linaro-lng-v4.1 (non-RT) branch is now capable of achieving extended periods of full tickless isolation.
<br>The release is also available via tags in the LNG git repository:
-bc. git://git.linaro.org/kernel/linux-linaro-lng.git linux-lng-3.14.44-2015.07
-git://git.linaro.org/kernel/linux-linaro-lng.git linux-lng-preempt-rt-3.14.43-2015.07
-git://git.linaro.org/kernel/linux-linaro-lng.git linux-lng-3.18.16-2015.07
-git://git.linaro.org/kernel/linux-linaro-lng.git linux-lng-preempt-rt-3.18.13-2015.07
+bc. git://git.linaro.org/kernel/linux-linaro-lng.git linux-lng-3.18.17-2015.08
+git://git.linaro.org/kernel/linux-linaro-lng.git linux-lng-preempt-rt-3.18.16-2015.08
+git://git.linaro.org/kernel/linux-linaro-lng.git linux-lng-4.1.4-2015.08
+git://git.linaro.org/kernel/linux-linaro-lng.git linux-lng-preempt-rt-4.1.3-2015.08
More information on Linaro Networking Group Kernels is available at
"http://wiki.linaro.org/LNG/Engineering/Foundational":http://wiki.linaro.org/LNG/Engineering/Foundational
@@ -21,8 +24,11 @@ h4. Fixed in this release
h4. Known issues
-NO_HZ_FULL isolation performance has been somewhat improved but continues to have issues in all current kernel branches due to upstream activity which caused a regression in isolation performance.
-This is actively being addressed at this time.
+NO_HZ_FULL isolation performance has been significantly improved in both branches of the LNG v3.18 kernels, and also in the 'non-RT' version of the LNG v4.1 kernel. However, NO_HZ_FULL isolation continues to be a 'work in progress' and still is not fully functional in the LNG v4.1 'RT' kernel.
+
+Extended periods of isolation presently come at the expense of CPU accounting accuracy on the isolated cores while running in 'full tickless' mode.
+
+CPU cores designated for use as 'full tickless' isolated cores are excluded from CPU load balancing, so CPU load balancing is effectively disabled on the LNG 3.18 kernels as currently configured. This is due to the compile-time configuration setting of CONFIG_NO_HZ_FULL_ALL=y, coupled with the fact that the allocation of CPUs as either 'nohz_full' or 'housekeeping' cores is statically defined at boot time. A work-around for the 3.18 kernels would be to configure the kernel with CONFIG_NO_HZ_FULL=y and CONFIG_NO_HZ_FULL_ALL=n, and then to use boot command line "nohz_full=..." CPU list parameter to apportion CPU resources appropriately. But for testing purposes the most convenient NO_HZ_FULL configuration is the one used in our kernel builds.
h4. Feedback and Support