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authorTadeusz Struk <tadeusz.struk@intel.com>2016-09-25 17:44:51 +0300
committerDoug Ledford <dledford@redhat.com>2016-10-02 15:42:19 +0300
commitc642cc070b4934cd4718e63aa46e140468bc6a60 (patch)
tree9b6e29b37f44a69637970325a7a8e4e322f09158 /Documentation/infiniband
parentaf3674d62d3470c4573709c031e6b17f1f39c96b (diff)
downloadlinux-c642cc070b4934cd4718e63aa46e140468bc6a60.tar.xz
IB/hfi1: Document new sysfs entries for hfi1 driver
This patch adds description for the sdma engine related sysfs entries for the HFI1 driver. Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com> Reviewed-by: Sebastian Sanchez <sebastian.sanchez@intel.com> Reviewed-by: Jianxin Xiong <jianxin.xiong@intel.com> Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'Documentation/infiniband')
-rw-r--r--Documentation/infiniband/sysfs.txt30
1 files changed, 30 insertions, 0 deletions
diff --git a/Documentation/infiniband/sysfs.txt b/Documentation/infiniband/sysfs.txt
index 45bcafe6ff8a..77570d16b170 100644
--- a/Documentation/infiniband/sysfs.txt
+++ b/Documentation/infiniband/sysfs.txt
@@ -89,6 +89,36 @@ HFI1
nctxts - number of allowed contexts (PSM2)
chip_reset - diagnostic (root only)
boardversion - board version
+
+ sdma<N>/ - one directory per sdma engine (0 - 15)
+ sdma<N>/cpu_list - read-write, list of cpus for user-process to sdma
+ engine assignment.
+ sdma<N>/vl - read-only, vl the sdma engine maps to.
+
+ The new interface will give the user control on the affinity settings
+ for the hfi1 device.
+ As an example, to set an sdma engine irq affinity and thread affinity
+ of a user processes to use the sdma engine, which is "near" in terms
+ of NUMA configuration, or physical cpu location, the user will do:
+
+ echo "3" > /proc/irq/<N>/smp_affinity_list
+ echo "4-7" > /sys/devices/.../sdma3/cpu_list
+ cat /sys/devices/.../sdma3/vl
+ 0
+ echo "8" > /proc/irq/<M>/smp_affinity_list
+ echo "9-12" > /sys/devices/.../sdma4/cpu_list
+ cat /sys/devices/.../sdma4/vl
+ 1
+
+ to make sure that when a process runs on cpus 4,5,6, or 7,
+ and uses vl=0, then sdma engine 3 is selected by the driver,
+ and also the interrupt of the sdma engine 3 is steered to cpu 3.
+ Similarly, when a process runs on cpus 9,10,11, or 12 and sets vl=1,
+ then engine 4 will be selected and the irq of the sdma engine 4 is
+ steered to cpu 8.
+ This assumes that in the above N is the irq number of "sdma3",
+ and M is irq number of "sdma4" in the /proc/interrupts file.
+
ports/1/
CCMgtA/
cc_settings_bin - CCA tables used by PSM2