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IB/hfi1: Document new sysfs entries for hfi1 driver

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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>
This commit is contained in:
Tadeusz Struk 2016-09-25 07:44:51 -07:00 committed by Doug Ledford
parent af3674d62d
commit c642cc070b
1 changed files with 30 additions and 0 deletions
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30
Documentation/infiniband/sysfs.txt
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@ -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