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umount_resctrlfs() directly attempts to unmount resctrl file system without
checking if resctrl FS is already mounted or not. It returns 0 on success
and on failure it prints an error message and returns an error status.
Calling umount_resctrlfs() when resctrl FS isn't mounted will return an
error status.
There could be situations where-in the caller might not know if resctrl
FS is already mounted or not and the caller might still want to unmount
resctrl FS if it's already mounted (For example during teardown).
To support above use cases, change umount_resctrlfs() such that it now
first checks if resctrl FS is already mounted or not and unmounts resctrl
FS only if it's already mounted.
unmount resctrl FS upon exit. For example, running only mba test on a
Broadwell (BDW) machine (MBA isn't supported on BDW CPU).
This happens because validate_resctrl_feature_request() would mount resctrl
FS to check if mba is enabled on the platform or not and finds that the H/W
doesn't support mba and hence will return false to run_mba_test(). This in
turn makes the main() function return without unmounting resctrl FS.
Tested-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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There could be two reasons why a resctrl feature might not be enabled on
the platform
1. H/W might not support the feature
2. Even if the H/W supports it, the user might have disabled the feature
through kernel command line arguments
Hence, any resctrl unit test (like cmt, cat, mbm and mba) before starting
the test will first check if the feature is enabled on the platform or not.
If the feature isn't enabled, then the test returns with an error status.
For example, if MBA isn't supported on a platform and if the user tries to
run MBA, the output will look like this
ok mounting resctrl to "/sys/fs/resctrl"
not ok MBA: schemata change
But, not supporting a feature isn't a test failure. So, instead of treating
it as an error, use the SKIP directive of the TAP protocol. With the
change, the output will look as below
ok MBA # SKIP Hardware does not support MBA or MBA is disabled
Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Resctrl test suite main() function does the following things
1. Parses command line arguments passed by user
2. Some setup checks
3. Logic that calls into each unit test
4. Print result and clean up after running each unit test
Introduce wrapper functions for steps 3 and 4 to modularize the main()
function. Adding these wrapper functions makes it easier to add any logic
to each individual test.
Please note that this is a preparatory patch for the next one and no
functional changes are intended.
Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Cache related tests (like CAT and CMT) depend on a variable called
no_of_bits to run. no_of_bits defines the number of contiguous bits
that should be set in the CBM mask and a user can pass a value for
no_of_bits using -n command line argument. If a user hasn't passed any
value, it defaults to 5 (randomly chosen value).
Hard coding no_of_bits to 5 will make the cache tests fail to run on
systems that support maximum cbm mask that is less than or equal to 5 bits.
Hence, don't hard code no_of_bits value.
If a user passes a value for "no_of_bits" using -n option, use it.
Otherwise, no_of_bits is equal to half of the maximum number of bits in
the cbm mask.
Please note that CMT test is still hard coded to 5 bits. It will change in
subsequent patches that change CMT test.
Tested-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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MBM unit test starts fill_buf (default built-in benchmark) in a new con_mon
group (c1, m1) and records resctrl reported mbm values and iMC (Integrated
Memory Controller) values every second. It does this for five seconds
(randomly chosen value) in total. It then calculates average of resctrl_mbm
values and imc_mbm values and if the difference is greater than 300 MB/sec
(randomly chosen value), the test treats it as a failure. MBA unit test is
similar to MBM but after every run it changes schemata.
Checking for a difference of 300 MB/sec doesn't look very meaningful when
the mbm values are changing over a wide range. For example, below are the
values running MBA test on SKL with different allocations
1. With 10% as schemata both iMC and resctrl mbm_values are around 2000
MB/sec
2. With 100% as schemata both iMC and resctrl mbm_values are around 10000
MB/sec
A 300 MB/sec difference between resctrl_mbm and imc_mbm values is
acceptable at 100% schemata but it isn't acceptable at 10% schemata because
that's a huge difference.
So, fix this by checking for percentage difference instead of absolute
difference i.e. check if the difference between resctrl_mbm value and
imc_mbm value is within 5% (randomly chosen value) of imc_mbm value. If the
difference is greater than 5% of imc_mbm value, treat it is a failure.
Tested-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Resctrl test suite before running any unit test (like cmt, cat, mbm and
mba) should first check if the feature is enabled (by kernel and not just
supported by H/W) on the platform or not.
validate_resctrl_feature_request() is supposed to do that. This function
intends to grep for relevant flags in /proc/cpuinfo but there are several
issues here
1. validate_resctrl_feature_request() calls fgrep() to get flags from
/proc/cpuinfo. But, fgrep() can only return a string with maximum of 255
characters and hence the complete cpu flags are never returned.
2. The substring search logic is also busted. If strstr() finds requested
resctrl feature in the cpu flags, it returns pointer to the first
occurrence. But, the logic negates the return value of strstr() and
hence validate_resctrl_feature_request() returns false if the feature is
present in the cpu flags and returns true if the feature is not present.
3. validate_resctrl_feature_request() checks if a resctrl feature is
reported in /proc/cpuinfo flags or not. Having a cpu flag means that the
H/W supports the feature, but it doesn't mean that the kernel enabled
it. A user could selectively enable only a subset of resctrl features
using kernel command line arguments. Hence, /proc/cpuinfo isn't a
reliable source to check if a feature is enabled or not.
The 3rd issue being the major one and fixing it requires changing the way
validate_resctrl_feature_request() works. Since, /proc/cpuinfo isn't the
right place to check if a resctrl feature is enabled or not, a more
appropriate place is /sys/fs/resctrl/info directory. Change
validate_resctrl_feature_request() such that,
1. For cat, check if /sys/fs/resctrl/info/L3 directory is present or not
2. For mba, check if /sys/fs/resctrl/info/MB directory is present or not
3. For cmt, check if /sys/fs/resctrl/info/L3_MON directory is present and
check if /sys/fs/resctrl/info/L3_MON/mon_features has llc_occupancy
4. For mbm, check if /sys/fs/resctrl/info/L3_MON directory is present and
check if /sys/fs/resctrl/info/L3_MON/mon_features has
mbm_<total/local>_bytes
Please note that only L3_CAT, L3_CMT, MBA and MBM are supported. CDP and L2
variants can be added later.
Reported-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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check_resctrlfs_support() does the following
1. Checks if the platform supports resctrl file system or not by looking
for resctrl in /proc/filesystems
2. Calls opendir() on default resctrl file system path
(i.e. /sys/fs/resctrl)
3. Checks if resctrl file system is mounted or not by looking at
/proc/mounts
Steps 2 and 3 will fail if the platform does not support resctrl file
system. So, there is no need to check for them if step 1 fails.
Fix this by returning immediately if the platform does not support
resctrl file system.
Tested-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Fenghua Yu