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-rw-r--r--Documentation/x86/resctrl_ui.rst30
1 files changed, 18 insertions, 12 deletions
diff --git a/Documentation/x86/resctrl_ui.rst b/Documentation/x86/resctrl_ui.rst
index 225cfd4daaee..5368cedfb530 100644
--- a/Documentation/x86/resctrl_ui.rst
+++ b/Documentation/x86/resctrl_ui.rst
@@ -40,7 +40,7 @@ mount options are:
Enable the MBA Software Controller(mba_sc) to specify MBA
bandwidth in MBps
-L2 and L3 CDP are controlled seperately.
+L2 and L3 CDP are controlled separately.
RDT features are orthogonal. A particular system may support only
monitoring, only control, or both monitoring and control. Cache
@@ -118,7 +118,7 @@ related to allocation:
Corresponding region is pseudo-locked. No
sharing allowed.
-Memory bandwitdh(MB) subdirectory contains the following files
+Memory bandwidth(MB) subdirectory contains the following files
with respect to allocation:
"min_bandwidth":
@@ -209,7 +209,7 @@ All groups contain the following files:
CPUs to/from this group. As with the tasks file a hierarchy is
maintained where MON groups may only include CPUs owned by the
parent CTRL_MON group.
- When the resouce group is in pseudo-locked mode this file will
+ When the resource group is in pseudo-locked mode this file will
only be readable, reflecting the CPUs associated with the
pseudo-locked region.
@@ -342,7 +342,7 @@ For cache resources we describe the portion of the cache that is available
for allocation using a bitmask. The maximum value of the mask is defined
by each cpu model (and may be different for different cache levels). It
is found using CPUID, but is also provided in the "info" directory of
-the resctrl file system in "info/{resource}/cbm_mask". X86 hardware
+the resctrl file system in "info/{resource}/cbm_mask". Intel hardware
requires that these masks have all the '1' bits in a contiguous block. So
0x3, 0x6 and 0xC are legal 4-bit masks with two bits set, but 0x5, 0x9
and 0xA are not. On a system with a 20-bit mask each bit represents 5%
@@ -380,7 +380,7 @@ where L2 external is 10GBps (hence aggregate L2 external bandwidth is
240GBps) and L3 external bandwidth is 100GBps. Now a workload with '20
threads, having 50% bandwidth, each consuming 5GBps' consumes the max L3
bandwidth of 100GBps although the percentage value specified is only 50%
-<< 100%. Hence increasing the bandwidth percentage will not yeild any
+<< 100%. Hence increasing the bandwidth percentage will not yield any
more bandwidth. This is because although the L2 external bandwidth still
has capacity, the L3 external bandwidth is fully used. Also note that
this would be dependent on number of cores the benchmark is run on.
@@ -398,7 +398,7 @@ In order to mitigate this and make the interface more user friendly,
resctrl added support for specifying the bandwidth in MBps as well. The
kernel underneath would use a software feedback mechanism or a "Software
Controller(mba_sc)" which reads the actual bandwidth using MBM counters
-and adjust the memowy bandwidth percentages to ensure::
+and adjust the memory bandwidth percentages to ensure::
"actual bandwidth < user specified bandwidth".
@@ -418,16 +418,22 @@ L3 schemata file details (CDP enabled via mount option to resctrl)
When CDP is enabled L3 control is split into two separate resources
so you can specify independent masks for code and data like this::
- L3data:<cache_id0>=<cbm>;<cache_id1>=<cbm>;...
- L3code:<cache_id0>=<cbm>;<cache_id1>=<cbm>;...
+ L3DATA:<cache_id0>=<cbm>;<cache_id1>=<cbm>;...
+ L3CODE:<cache_id0>=<cbm>;<cache_id1>=<cbm>;...
L2 schemata file details
------------------------
-L2 cache does not support code and data prioritization, so the
-schemata format is always::
+CDP is supported at L2 using the 'cdpl2' mount option. The schemata
+format is either::
L2:<cache_id0>=<cbm>;<cache_id1>=<cbm>;...
+or
+
+ L2DATA:<cache_id0>=<cbm>;<cache_id1>=<cbm>;...
+ L2CODE:<cache_id0>=<cbm>;<cache_id1>=<cbm>;...
+
+
Memory bandwidth Allocation (default mode)
------------------------------------------
@@ -671,8 +677,8 @@ allocations can overlap or not. The allocations specifies the maximum
b/w that the group may be able to use and the system admin can configure
the b/w accordingly.
-If the MBA is specified in MB(megabytes) then user can enter the max b/w in MB
-rather than the percentage values.
+If resctrl is using the software controller (mba_sc) then user can enter the
+max b/w in MB rather than the percentage values.
::
# echo "L3:0=3;1=c\nMB:0=1024;1=500" > /sys/fs/resctrl/p0/schemata