linux-dev - Linux kernel development work

Age	Commit message (Collapse)	Author	Files	Lines
2014-07-28	selftests/powerpc: Count more instructions & use decimal	Michael Ellerman	1	-8/+14
	Although we expect some small discrepancies for very large counts, we seem to be able to count up to 64 billion instructions without too much skew, so do so. Also switch to using decimals for the instruction counts. This just makes it easier to visually compare the expected vs actual values, as well as the raw result from instructions. Before: instructions: result 68719476753 running/enabled 13101961654 cycles: result 38077343785 running/enabled 13101725752 Looped for 68719476736 instructions, overhead 17 Expected 68719476753 Actual 68719476753 Delta 0, 0.000000% success: count_instructions After: instructions: result 64000000016 running/enabled 12197599964 cycles: result 35412471674 running/enabled 12197534110 Looped for 64000000000 instructions, overhead 16 Expected 64000000016 Actual 64000000016 Delta 0, 0.000000% success: count_instructions Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-07-28	selftests/powerpc: Count instructions under scheduler pressure	Michael Ellerman	1	-1/+7
	Have a task eat some cpu while we are counting instructions to create some scheduler pressure. The idea being to try and unearth any bugs we have in counting that only appear when context switching is happening. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-08-14	selftests: Add test of PMU instruction counting on powerpc	Michael Ellerman	1	-0/+135
	This commit adds a test of instruction counting using the PMU on powerpc. Although the bulk of the code is architecture agnostic, the code needs to run a precisely sized loop which is implemented in assembler. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>