aboutsummaryrefslogtreecommitdiffstats
path: root/tools/testing/selftests/rcutorture (follow)
AgeCommit message (Collapse)AuthorFilesLines
2016-11-14torture: Prevent jitter from delaying build-only runsPaul E. McKenney1-0/+5
Currently, if the --jitter flag specifies jitter for a --build-only run, the system will obediently build a kernel, refuse to launch it, launch the requested number of jitter processes, and wait for the specified kernel run time, which defaults to 30 minutes. This is of course quite pointless. This commit therefore disables jitter on build-only runs. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2016-11-14torture: Remove obsolete files from rcutorture .gitignorePaul E. McKenney1-2/+0
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2016-06-14torture: Inflict default jitterPaul E. McKenney1-1/+1
This commit enables jitter by default. It may be manually disabled by passing "--jitter 0" to kvm.sh. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-06-14rcutorture: Drop "-soundhw pcspkr" from x86 boot argumentsPaul E. McKenney1-1/+0
Because recent testing shows that "-soundhw pcspkr" is no longer required in the kernel boot arguments, this commit drops this qemu argument. Reported-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-06-14rcutorture: Don't specify the cpu type of QEMU on PPCBoqun Feng1-1/+1
Do not restrict the cpu type to POWER7 for QEMU as we have POWER8 now. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-06-14rcutorture: Make -soundhw a x86 specific optionBoqun Feng2-4/+5
The option "-soundhw pcspk" gives me a error on PPC as follow: qemu-system-ppc64: ISA bus not available for pcspk This means this option doesn't work on ppc by default. So simply make this an x86-specific option via identify_qemu_args(). Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-06-14rcutorture: Use vmlinux as the fallback kernel imageBoqun Feng2-8/+7
The vmlinux image is available for all the architectures, and suitable for running a KVM guest by QEMU, besides, we used to copy the vmlinux to $resdir anyway. Therefore it makes sense to use it as the fallback kernel image for rcutorture KVM tests. This patch makes identify_boot_image() return vmlinux if ${TORTURE_BOOT_IMAGE} is not set on non-x86 architectures, also fixes several places that hard-code "bzImage" as $KERNEL. This also fixes a problem that PPC doesn't have a bzImage file as build results. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-06-14rcutorture/doc: Create initrd using dracutBoqun Feng1-0/+22
Using dracut is another way to get an initramfs for KVM-based RCU torture tests, which is more flexible than using the host's initramfs image, because modules and binaries may be added or removed via dracut command options. So add an example in the document, in case that there are some situations where host's initramfs couldn't be used. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-06-14torture: Add starvation events to error summaryPaul E. McKenney1-1/+6
This commit adds a string of the form "Starves: 10" to the summary line for error conditions found in the console output. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-06-14torture: Forgive lengthy trace dumps and preemptionPaul E. McKenney1-2/+19
This commit avoids killing qemu if a trace dump is making progress or if console log output is continuing and the console log timestamp does not exceed the total plus grace period. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-04-21rcutorture: Add boot-time adjustment of leaf fanoutPaul E. McKenney2-2/+2
Currently, the rcutorture scripts do not test boot-time adjustment of leaf fanout (via the rcutree.rcu_fanout_leaf boot parameter), as was noted during testing carried out by Iftekhar Ahmed of Oregon State University. This commit therefore adjusts TREE04's CONFIG_RCU_FANOUT_LEAF from 4 to 3, and also adds rcutree.rcu_fanout_leaf=4 to its boot parameters. This change forces RCU's boot-time geometry-change code to be exercised. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-04-21rcutorture: Don't rebuild identical kernelPaul E. McKenney1-7/+19
Currently, if the user specifies multiple runs of a given test configuration, the scripting does multiple kernel builds. This wastes both time and disk space, so this commit makes the scripting use the first build for all runs of a given test configuration. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-04-21rcutorture: Add OS-jitter capabilityPaul E. McKenney2-0/+108
This commit adds a --jitter OS-jitter capability to expose bugs based on no-delay assumptions. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-03-31rcutorture: Convert test duration to seconds earlyPaul E. McKenney2-5/+4
This commit converts test duration from minutes to seconds early on in order to prepare for upcoming OS-jitter-injection changes. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-03-31torture: Kill qemu, not parent processPaul E. McKenney1-6/+24
The current hang-check machinery in the rcutorture scripts uses "$!" of a parenthesized bash statement to capture the pid. Unfortunately, this captures not qemu's pid, but rather that of its parent that implements the parenthesized statement. This commit therefore adjusts things so as to capture qemu's actual pid, which then allows the script to actually kill qemu in event of a kernel hang. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-03-31rcutorture: Add largish-system rcuperf scenarioPaul E. McKenney1-0/+23
This commit adds an rcuperf scenario named TREE54 that uses 54 CPUs and provides a four-level rcu_node combining tree. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-03-31rcutorture: Make scripts analyze rcuperf trace data, if presentPaul E. McKenney2-0/+129
The rcuperf event-trace data is more accurate than are the rcuperf printk()s because locking keeps things ordered. This commit therefore parses and analyzes this event-trace data if present, and falls back on the printk()s otherwise. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-03-31rcutorture: Make rcuperf collect expedited event-trace dataPaul E. McKenney1-0/+1
This commit enables ftrace in the rcuperf TREE kernel build and adds an ftrace_dump() at the end of rcuperf processing. This data will be used to measure the actual durations of the expedited grace periods without the added delays inherent in the kernel-module measurements. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-03-31rcutorture: Print measure of batching efficiencyPaul E. McKenney1-10/+16
This commit adds a line giving the number of grace periods, the number of batches, and the ratio. The larger the ratio, the greater the batching efficiency. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-03-31rcutorture: Update scripting to accommodate rcuperfPaul E. McKenney7-2/+161
This commit adds the scripting changes to add support for the shiny new rcuperf kernel module. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-01-25rcutorture: Check for self-detected stallsPaul E. McKenney1-2/+2
The current scripts parse console output only for cases where one CPU detect a stall on some other CPU or task. This commit therefore adds checks for self-detected stalls. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-01-25rcutorture: Don't keep empty console.log.diags filesPaul E. McKenney1-0/+2
Currently, an error-free run produces an empty console.log.diags file. This can be annoying when using "vi */console.log.diags" to see a full summary of the errors. This commit therefore removes any empty files during the analysis process. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-01-25rcutorture: Add checks for rcutorture writer starvationPaul E. McKenney1-2/+2
This commit adds checks for rcutorture writer starvation, so that instances will be added to the test summary. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2015-12-05torture: Place console.log files correctly from the get-goPaul E. McKenney1-3/+2
Currently, the console output files ("console.log") are placed in the build directory initially, then copied to the results directory. One problem with this is if a qemu refuses to die in a timely fashion after a kernel hang, it will continue to write after the next qemu starts up, resulting in confusing output from the old instance of qemu. This commit prevents such confusion by placing the console.log files into the results directory to begin with, so that a given instance of qemu is always writing only to its own console.log file. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-12-05torture: Abbreviate console error dumpPaul E. McKenney1-6/+35
Currently, the scripts print a list of warning/bug indicators from the console.log file. This works well if there are only a few warnings or bugs, but can be quite annoying if there is a large number. This commit therefore prints a summary listing the number of each type of warning/bug indicator, but only if there is at least one such indicator. The full list is stored in the results directory at console.log.diags, which makes it easier to find the warning/bugs in the full console.log. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-12-05rcutorture: Remove CONFIG_RCU_USER_QS from rcutorture selftest docYang Shi2-5/+0
Commit d1ec4c34c7a9 ("rcu: Drop RCU_USER_QS in favor of NO_HZ_FULL") has removed RCU_USER_QS from Kconfig file, so remove it from some documents to avoid any confusion. Signed-off-by: Yang Shi <yang.shi@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-12-05rcutorture: Default grace period to three minutes, allow overridePaul E. McKenney2-3/+8
The default test grace period of two minutes is insufficient in some cases and excessive in others. This commit therefore increases the default to three minutes, but also adds a --shutdown-grace parameter to allow the default to be overridden. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-12-05rcutorture: Add batch number to script printoutPaul E. McKenney1-6/+9
Currently, the scripts print "----Start batch" at the beginning of each batch, which does serve as a good visual delimiter between batches. Unfortunately, if there are a lot of batches, it is hard to quickly estimate test runtime from the output of "--dryrun sched". This commit therefore adds a batch number, so that the beginning-of-batch output looks like this "----Start batch 10" for the tenth batch. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-10-07Merge branches 'doc.2015.10.06a', 'percpu-rwsem.2015.10.06a' and 'torture.2015.10.06a' into HEADPaul E. McKenney6-4/+20
doc.2015.10.06a: Documentation updates. percpu-rwsem.2015.10.06a: Optimization of per-CPU reader-writer semaphores. torture.2015.10.06a: Torture-test updates.
2015-10-06torture: Forgive non-plural argumentsPaul E. McKenney1-3/+3
This commit allows --bootarg instead of --bootargs, --config instead of --configs, and --qemu-arg instead of --qemu-args. For those cases where a native English speaker might auto-correct the argument to be incorrect. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-10-06locktorture: Add torture tests for percpu_rwsemPaul E. McKenney3-0/+8
This commit adds percpu_rwsem tests based on the earlier rwsem tests. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-10-06locktorture: Support rtmutex torturingDavidlohr Bueso3-1/+9
Real time mutexes is one of the few general primitives that we do not have in locktorture. Address this -- a few considerations: o To spice things up, enable competing thread(s) to become rt, such that we can stress different prio boosting paths in the rtmutex code. Introduce a ->task_boost callback, only used by rtmutex-torturer. Tasks will boost/deboost around every 50k (arbitrarily) lock/unlock operations. o Hold times are similar to what we have for other locks: only occasionally having longer hold times (per ~200k ops). So we roughly do two full rt boost+deboosting ops with short hold times. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-08-04Merge branches 'doc.2015.07.15a' and 'torture.2015.07.15a' into HEADPaul E. McKenney1-2/+2
doc.2015.07.15a: Documentation updates. torture.2015.07.15a: Torture-test updates.
2015-07-17rcu: Remove CONFIG_RCU_CPU_STALL_INFOPaul E. McKenney12-12/+0
The CONFIG_RCU_CPU_STALL_INFO has been default-y for a couple of releases with no complaints, so it is time to eliminate this Kconfig option entirely, so that the long-form RCU CPU stall warnings cannot be disabled. This commit does just that. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2015-07-15rcutorture: Enable lockdep-RCU on TASKS01Paul E. McKenney1-2/+2
Currently none of the RCU-tasks scenarios enables lockdep-RCU, which causes bugs to be missed. This commit therefore enables lockdep-RCU on TASKS01. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2015-05-27Merge branches 'array.2015.05.27a', 'doc.2015.05.27a', 'fixes.2015.05.27a', 'hotplug.2015.05.27a', 'init.2015.05.27a', 'tiny.2015.05.27a' and 'torture.2015.05.27a' into HEADPaul E. McKenney28-56/+72
array.2015.05.27a: Remove all uses of RCU-protected array indexes. doc.2015.05.27a: Docuemntation updates. fixes.2015.05.27a: Miscellaneous fixes. hotplug.2015.05.27a: CPU-hotplug updates. init.2015.05.27a: Initialization/Kconfig updates. tiny.2015.05.27a: Updates to Tiny RCU. torture.2015.05.27a: Torture-testing updates.
2015-05-27rcutorture: Allow repetition factors in Kconfig-fragment listsPaul E. McKenney1-6/+19
Although it is currently possible to run the same test in parallel, '--config "TINY01 TINY01 TINY01"' can get a bit verbose, especially if you want to run 48 instances of TINY01 in parallel. This commit therefore allows prefixing the Kconfig fragment with a repeat count, for example, '--config "48*TINY01"' to run 48 instances in parallel. At least assuming that you have 48 CPUs and also gave '--cpus 48'. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-05-27rcutorture: Display "make oldconfig" errorsPaul E. McKenney2-1/+5
The current rcutorture scripting fails to dump out errors from "make oldconfig", so this commit addresses this issue. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-05-27rcutorture: Update TREE_RCU-kconfig.txtPaul E. McKenney8-30/+21
This commit updates TREE_RCU-kconfig.txt to reflect changes in RCU's Kconfig setup. This commit also updates rcutorture's Kconfig fragments to account for Kconfig parameters that are now driven directly off of other Kconfig parameters. The #CHECK# prefix tells the rcutorture scripts to take no action to try to set the Kconfig parameter, but to check that it does in fact get set. This is useful for verifying that Kconfig parameters that are supposed to be automatically set do in fact get set to the required values. Reported-by: Pranith Kumar <bobby.prani@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-05-27rcutorture: Make rcutorture scripts force RCU_EXPERTPaul E. McKenney13-0/+13
This commit causes the rcutorture scripts to force RCU_EXPERT so that these scripts can cause rcutorture to torture RCU in the various required configurations. However, SRCU-P, TASKS03, and TREE09 retain !RCU_EXPERT in order to ensure testing of the vanilla configuration. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Pranith Kumar <bobby.prani@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-05-27rcutorture: Update configuration fragments for rcutree.rcu_fanout_exactPaul E. McKenney12-9/+3
This commit updates rcutortures configuration-fragment files to account for the move from the CONFIG_RCU_FANOUT_EXACT Kconfig parameter to the new rcutree.rcu_fanout_exact= boot parameter. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Pranith Kumar <bobby.prani@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-05-27rcutorture: TASKS_RCU set directly, so don't explicitly set itPaul E. McKenney3-3/+0
The TASKS01, TASKS02, and TASKS03 rcutorture config fragments currently set CONFIG_TASKS_RCU. However, now that the value of this Kconfig parameter is set via "select" statements, it is no longer necessary to set it explicitly. This commit therefore removes it from the Kconfig fragments. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Pranith Kumar <bobby.prani@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-05-27rcutorture: Test SRCU cleanup code pathPaul E. McKenney1-1/+1
The current rcutorture testing does not do any cleanup operations. This works because the srcu_struct is statically allocated, but it does represent a memory leak of the associated dynamically allocated ->per_cpu_ref per-CPU variables. However, rcutorture currently uses a statically allocated srcu_struct, which cannot legally be passed to cleanup_srcu_struct(). Therefore, this commit adds a second form of srcu (called srcud) that dynamically allocates and frees the associated per-CPU variables. This commit also adds a ->cleanup() member to rcu_torture_ops that is invoked at the end of the test, after ->cb_barriers(). This ->cleanup() pointer is NULL for all existing tests, and thus only used for scrud. Finally, the SRCU-P torture-test configuration selects scrud instead of srcu, with SRCU-N continuing to use srcu, thereby testing both static and dynamic srcu_struct structures. Reported-by: "Ahmed, Iftekhar" <ahmedi@onid.oregonstate.edu> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-05-27rcutorture: Exchange TREE03 and TREE08 NR_CPUS, speed up CPU hotplugPaul E. McKenney3-2/+3
TREE03 has been especially effective at finding bugs lately. This commit makes it even more effective by speeding up its CPU hotplug testing and increasing its NR_CPUs from 8 to 16. TREE08's NR_CPUS is decreased from 16 to 8 in order to maintain the same test duration. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-05-27rcutorture: Exchange TREE03 and TREE04 geometriesPaul E. McKenney2-4/+4
Given that the combination of PREEMPT_RCU and HOTPLUG_CPU is producing the most bugs lately, this commit swaps the TREE03 and TREE04 rcu_node-tree geometries so that the test exercising PREEMPT_RCU and HOTPLUG_CPU has three-level rather than two-level rcu_node trees. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-05-27rcutorture: Test both RCU-sched and RCU-bh for Tiny RCUPaul E. McKenney1-0/+1
Tiny RCU supports both RCU-sched and RCU-bh, but only RCU-sched is currently tested by the rcutorture scripts. This commit therefore changes the TINY02 configuration to test RCU-bh, with TINY01 continuing to test RCU-sched. This shortcoming of the current rcutorture tests was located by mutation testing by Iftekhar. The idea behind mutation testing is to automatically mutate the code under test. If a given mutant is not caught by testing, this is a hint that the testing might need to be improved, as was the case here. Note that this is only a hint because it is possible to mutate the code into something else that still works. For example, a mutation that removes (say) a WARN_ON() will not normally result in a test failure. This change resulted in the test failure caused by list mishandling, which is fixed by the next commit. Reported-by: "Ahmed, Iftekhar" <ahmedi@onid.oregonstate.edu> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-05-27rcu: Provide diagnostic option to slow down grace-period scansPaul E. McKenney1-0/+2
Grace-period scans of the rcu_node combining tree normally proceed quite quickly, so that it is very difficult to reproduce races against them. This commit therefore allows grace-period pre-initialization and cleanup to be artificially slowed down, increasing race-reproduction probability. A pair of pairs of new Kconfig parameters are provided, RCU_TORTURE_TEST_SLOW_PREINIT to enable the slowing down of propagating CPU-hotplug changes up the combining tree along with RCU_TORTURE_TEST_SLOW_PREINIT_DELAY to specify the delay in jiffies, and RCU_TORTURE_TEST_SLOW_CLEANUP to enable the slowing down of the end-of-grace-period cleanup scan along with RCU_TORTURE_TEST_SLOW_CLEANUP_DELAY to specify the delay in jiffies. Boot-time parameters named rcutree.gp_preinit_delay and rcutree.gp_cleanup_delay allow these delays to be specified at boot time. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2015-03-20Merge branches 'doc.2015.02.26a', 'earlycb.2015.03.03a', 'fixes.2015.03.03a', 'gpexp.2015.02.26a', 'hotplug.2015.03.20a', 'sysidle.2015.02.26b' and 'tiny.2015.02.26a' into HEADPaul E. McKenney2-1/+2
doc.2015.02.26a: Documentation changes earlycb.2015.03.03a: Permit early-boot RCU callbacks fixes.2015.03.03a: Miscellaneous fixes gpexp.2015.02.26a: In-kernel expediting of normal grace periods hotplug.2015.03.20a: CPU hotplug fixes sysidle.2015.02.26b: NO_HZ_FULL_SYSIDLE fixes tiny.2015.02.26a: TINY_RCU fixes
2015-03-11rcutorture: Enable slow grace-period initializationsPaul E. McKenney1-0/+1
This commit sets CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y, but leaves the default time zero. This can be overridden by passing the "--bootargs rcutree.gp_init_delay=1" argument to kvm.sh. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2015-03-03torture: Avoid script syntax error when insufficient CPUsPaul E. McKenney1-1/+1
Parentheses are special to bash, so use an overflow flag that doesn't use them. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>