Commit 85ba6bfe authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

torture: Provide more sensible nreader/nwriter defaults for rcuperf 



The default values for nreader and nwriter are apparently not all that
user-friendly, resulting in people doing scalability tests that ran all
runs at large scale.  This commit therefore makes both the nreaders and
nwriters module default to the number of CPUs, and adds a comment to
rcuperf.c stating that the number of CPUs should be specified using the
nr_cpus kernel boot parameter.  This commit also eliminates the redundant
rcuperf scripting specification of default values for these parameters.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 0da8c08d

kernel/rcu/rcuperf.c

+20 −1
Original line number Diff line number Diff line
@@ -61,11 +61,30 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.vnet.ibm.com>"); 
#define VERBOSE_PERFOUT_ERRSTRING(s) \

	do { if (verbose) pr_alert("%s" PERF_FLAG "!!! %s\n", perf_type, s); } while (0)



/*

 * The intended use cases for the nreaders and nwriters module parameters

 * are as follows:

 *

 * 1.	Specify only the nr_cpus kernel boot parameter.  This will

 *	set both nreaders and nwriters to the value specified by

 *	nr_cpus for a mixed reader/writer test.

 *

 * 2.	Specify the nr_cpus kernel boot parameter, but set

 *	rcuperf.nreaders to zero.  This will set nwriters to the

 *	value specified by nr_cpus for an update-only test.

 *

 * 3.	Specify the nr_cpus kernel boot parameter, but set

 *	rcuperf.nwriters to zero.  This will set nreaders to the

 *	value specified by nr_cpus for a read-only test.

 *

 * Various other use cases may of course be specified.

 */



torture_param(bool, gp_async, false, "Use asynchronous GP wait primitives");

torture_param(int, gp_async_max, 1000, "Max # outstanding waits per reader");

torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");

torture_param(int, holdoff, 10, "Holdoff time before test start (s)");

torture_param(int, nreaders, 0, "Number of RCU reader threads");

torture_param(int, nreaders, -1, "Number of RCU reader threads");

torture_param(int, nwriters, -1, "Number of RCU updater threads");

torture_param(bool, shutdown, !IS_ENABLED(MODULE),

	      "Shutdown at end of performance tests.");

tools/testing/selftests/rcutorture/configs/rcuperf/ver_functions.sh

+1 −23
Original line number Diff line number Diff line
@@ -20,32 +20,10 @@ 
#

# Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>



# rcuperf_param_nreaders bootparam-string

#

# Adds nreaders rcuperf module parameter if not already specified.

rcuperf_param_nreaders () {

	if ! echo "$1" | grep -q "rcuperf.nreaders"

	then

		echo rcuperf.nreaders=-1

	fi

}



# rcuperf_param_nwriters bootparam-string

#

# Adds nwriters rcuperf module parameter if not already specified.

rcuperf_param_nwriters () {

	if ! echo "$1" | grep -q "rcuperf.nwriters"

	then

		echo rcuperf.nwriters=-1

	fi

}



# per_version_boot_params bootparam-string config-file seconds

#

# Adds per-version torture-module parameters to kernels supporting them.

per_version_boot_params () {

	echo $1 `rcuperf_param_nreaders "$1"` \

		`rcuperf_param_nwriters "$1"` \

		rcuperf.shutdown=1 \

	echo $1 rcuperf.shutdown=1 \

		rcuperf.verbose=1

}

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