Executive Summary: - The PTI feature increases the system call times by more than 100%. - As a macrobenchmark, buildworld was used. Wall clock and user time showed no statistically-significant changes, while system time increased by less than 5%. This email contains the results for benchmarking the performance of the PTI patch on FreeBSD 12-current. As a microbenchmark, timing of getppid(2) system call was used, and as a macrobenchmark, a number of buildworld tasks were timed. The benchmark cases are as follows: 1. PTI off, PCID off 2. PTI off, PCID on 3. PTI on , PCID off 4. PTI on , PCID on Since PCID is an optimization and is usually enabled by default, the two most interesting cases above are the cases (2) and (4). Other cases were measured for demonstration of PCID's effect on overall time. The results section for each test is the output of ministat(1) for all the data gathered for that test. Ministat compares the first input file with all the other input files and reports the difference. For more information, check out the man page of ministat(1). ********************************** REVISION: HEAD (b21ccf63f28) ********************************** ************************** Benchmark: Syscall microbenchmark from tools/tools/syscall_timing ./syscall_timing getppid ************************** **************** Hardware: Packet's baremetal type 2 2 x Intel(R) Xeon(TM) CPU E5-2650 v4 (24 cores _at_ 2.20GHz) 256GB DDR4 ECC RAM 2.8TB SSD **************** ******** results: ******** x pti-off-pcid-on.log + pti-off-pcid-off.log * pti-on-pcid-off.log % pti-on-pcid-on.log +------------------------------------------------------------------------+ | * % * | | * % * | | * % * | | * % * | | * %% ** | | * +x + x %% % *O * *| ||_MA_|| |__M__A____| |___M___A_______| | +------------------------------------------------------------------------+ N Min Max Median Avg Stddev x 10 118 162 118 123.9 14.192721 + 10 118 154 118 122.5 11.42366 No difference proven at 95.0% confidence * 10 339 454 340 356.4 37.883447 Difference at 95.0% confidence 232.5 +/- 26.8779 187.651% +/- 29.8653% (Student's t, pooled s = 28.6058) % 10 262 342 262 272.2 25.301735 Difference at 95.0% confidence 148.3 +/- 19.2744 119.693% +/- 21.5323% (Student's t, pooled s = 20.5135) ********************************** REVISION: HEAD (c9cf79445478) ********************************** ************************** Benchmark: buildworld, invoked with this command: make -C /usr/src -j48 buildworld > build.log 2>&1 ************************** **************** Hardware: Packet's baremetal type 2 2 x Intel(R) Xeon(TM) CPU E5-2650 v4 (24 cores _at_ 2.20GHz) 256GB DDR4 ECC RAM 2.8TB SSD **************** ******** results: ******** x real-pti-off-pcid-on.log + real-pti-off-pcid-off.log * real-pti-on-pcid-off.log % real-pti-on-pcid-on.log +------------------------------------------------------------------------+ | x + % x % + % * * + x *| ||______________|_|___M_A__AMAM|___|____M_|_____|_A__________________| | +------------------------------------------------------------------------+ N Min Max Median Avg Stddev x 3 1677.08 1712.18 1691.4 1693.5533 17.6488 + 3 1686.9 1706.72 1697.84 1697.1533 9.9278262 No difference proven at 95.0% confidence * 3 1703.57 1729.55 1705.3 1712.8067 14.52593 No difference proven at 95.0% confidence % 3 1688.69 1701.44 1695.96 1695.3633 6.3959075 No difference proven at 95.0% confidence x user-pti-off-pcid-on.log + user-pti-off-pcid-off.log * user-pti-on-pcid-off.log % user-pti-on-pcid-on.log +--------------------------------------------------------------------------+ | *+ x % % +x % * * *| ||_|__M____MA_A_|______M_|_A__________| |___MA_____|| +--------------------------------------------------------------------------+ N Min Max Median Avg Stddev x 3 50223.23 50409.49 50273.89 50302.203 96.303845 + 3 50226.37 50401.75 50230.85 50286.323 99.98752 No difference proven at 95.0% confidence * 3 50754.05 50842.26 50781.66 50792.657 45.121459 Difference at 95.0% confidence 490.453 +/- 170.45 0.975014% +/- 0.341564% (Student's t, pooled s = 75.201) % 3 50342.4 50535.65 50380.41 50419.487 102.37983 No difference proven at 95.0% confidence x sys-pti-off-pcid-on.log + sys-pti-off-pcid-off.log * sys-pti-on-pcid-off.log % sys-pti-on-pcid-on.log +--------------------------------------------------------------------------+ |+x + x+x % %% * * * | ||_|____A__A___M|__| |_____A_M__| |__________A_M_______|| +--------------------------------------------------------------------------+ N Min Max Median Avg Stddev x 3 2623.5 2658.68 2652.31 2644.83 18.74489 + 3 2620.79 2654.58 2637.55 2637.64 16.89518 No difference proven at 95.0% confidence * 3 2740.31 2787.22 2772.59 2766.7067 24.002026 Difference at 95.0% confidence 121.877 +/- 48.8099 4.60811% +/- 1.87816% (Student's t, pooled s = 21.5345) % 3 2710.22 2733.57 2730.79 2724.86 12.75458 Difference at 95.0% confidence 80.03 +/- 36.338 3.0259% +/- 1.40248% (Student's t, pooled s = 16.032)Received on Thu Mar 08 2018 - 21:04:12 UTC
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