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| author |   Santosh Sivaraj <santosh@fossix.org> | 2017-10-16 11:19:14 +0530 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2017-12-04 15:01:09 +1100 |
| commit | 5c929885f1bb4b77f85b1769c49405a0e0f154a1 (patch) | |
| tree | 25917723f5393257b386deef8f796bb36e71de8d /tools/testing/selftests/powerpc/tm | |
| parent | ps3: Remove deprecated create_singlethread_workqueue (diff) | |
| download | linux-dev-5c929885f1bb4b77f85b1769c49405a0e0f154a1.tar.xz linux-dev-5c929885f1bb4b77f85b1769c49405a0e0f154a1.zip | |
powerpc/vdso64: Add support for CLOCK_{REALTIME/MONOTONIC}_COARSE
Current vDSO64 implementation does not have support for coarse clocks
(CLOCK_MONOTONIC_COARSE, CLOCK_REALTIME_COARSE), for which it falls back
to system call, increasing the response time, vDSO implementation reduces
the cycle time. Below is a benchmark of the difference in execution times.
(Non-coarse clocks are also included just for completion)
clock-gettime-realtime: syscall: 172 nsec/call
clock-gettime-realtime: libc: 28 nsec/call
clock-gettime-realtime: vdso: 22 nsec/call
clock-gettime-monotonic: syscall: 171 nsec/call
clock-gettime-monotonic: libc: 30 nsec/call
clock-gettime-monotonic: vdso: 25 nsec/call
clock-gettime-realtime-coarse: syscall: 153 nsec/call
clock-gettime-realtime-coarse: libc: 16 nsec/call
clock-gettime-realtime-coarse: vdso: 10 nsec/call
clock-gettime-monotonic-coarse: syscall: 167 nsec/call
clock-gettime-monotonic-coarse: libc: 17 nsec/call
clock-gettime-monotonic-coarse: vdso: 11 nsec/call
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'tools/testing/selftests/powerpc/tm')
0 files changed, 0 insertions, 0 deletions