Add profiling hooks for using perf

Signed-off-by: Mel Gorman <mgorman@suse.de>
pgbench: More transactions

Signed-off-by: Mel Gorman <mgorman@suse.de>
sysbench: More transactions

Signed-off-by: Mel Gorman <mgorman@suse.de>
pipetest: More iterations

Signed-off-by: Mel Gorman <mgorman@suse.de>
Record error stream

Signed-off-by: Mel Gorman <mgorman@suse.de>
sysbench: Convert to new basic format

Signed-off-by: Mel Gorman <mgorman@suse.de>
sysbench: Update to new format

Signed-off-by: Mel Gorman <mgorman@suse.de>
Update testcase documentation

Signed-off-by: Mel Gorman <mgorman@suse.de>