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Revision tags: v5.15.10, v5.15.9, v5.15.8, v5.15.7, v5.15.6, v5.15.5, v5.15.4, v5.15.3, v5.15.2, v5.15.1, v5.15, v5.14.14, v5.14.13, v5.14.12, v5.14.11, v5.14.10, v5.14.9, v5.14.8, v5.14.7, v5.14.6, v5.10.67, v5.10.66, v5.14.5, v5.14.4, v5.10.65, v5.14.3, v5.10.64, v5.14.2, v5.10.63, v5.14.1, v5.10.62, v5.14, v5.10.61, v5.10.60, v5.10.53, v5.10.52, v5.10.51, v5.10.50, v5.10.49, v5.13, v5.10.46, v5.10.43, v5.10.42, v5.10.41, v5.10.40, v5.10.39, v5.4.119, v5.10.36, v5.10.35, v5.10.34, v5.4.116, v5.10.33, v5.12, v5.10.32, v5.10.31, v5.10.30, v5.10.27, v5.10.26, v5.10.25, v5.10.24, v5.10.23, v5.10.22, v5.10.21, v5.10.20, v5.10.19, v5.4.101, v5.10.18, v5.10.17, v5.11, v5.10.16, v5.10.15, v5.10.14, v5.10, v5.8.17, v5.8.16, v5.8.15, v5.9, v5.8.14, v5.8.13, v5.8.12, v5.8.11, v5.8.10, v5.8.9, v5.8.8, v5.8.7, v5.8.6, v5.4.62, v5.8.5, v5.8.4, v5.4.61, v5.8.3, v5.4.60, v5.8.2, v5.4.59, v5.8.1, v5.4.58, v5.4.57, v5.4.56, v5.8, v5.7.12, v5.4.55, v5.7.11, v5.4.54, v5.7.10, v5.4.53, v5.4.52, v5.7.9, v5.7.8, v5.4.51, v5.4.50, v5.7.7, v5.4.49, v5.7.6 |
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| #
e93b327d |
| 23-Jun-2020 |
Vincent Chen <vincent.chen@sifive.com> |
riscv: Add extern declarations for vDSO time-related functions
Add extern declarations for vDSO time-related functions to notify the
compiler these functions will be used in somewhere to avoid
"no p
riscv: Add extern declarations for vDSO time-related functions
Add extern declarations for vDSO time-related functions to notify the
compiler these functions will be used in somewhere to avoid
"no previous prototype" compile warning.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
show more ...
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|
Revision tags: v5.7.5, v5.4.48, v5.7.4, v5.7.3, v5.4.47, v5.4.46, v5.7.2 |
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| #
ad5d1122 |
| 09-Jun-2020 |
Vincent Chen <vincent.chen@sifive.com> |
riscv: use vDSO common flow to reduce the latency of the time-related functions
Even if RISC-V has supported the vDSO feature, the latency of the functions
for obtaining the system time is still exp
riscv: use vDSO common flow to reduce the latency of the time-related functions
Even if RISC-V has supported the vDSO feature, the latency of the functions
for obtaining the system time is still expensive. It is because these
functions still trigger a corresponding system call in the process, which
slows down the response time. If we want to remove the system call to
reduce the latency, the kernel should have the ability to output the system
clock information to userspace. This patch introduces the vDSO common flow
to enable the kernel to achieve the above feature and uses "rdtime"
instruction to obtain the current time in the user space. Under this
condition, the latency cost by the ecall from U-mode to S-mode can be
eliminated. After applying this patch, the latency of gettimeofday()
measured on the HiFive unleashed board can be reduced by %61.
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
show more ...
|
|
Revision tags: v5.15.10, v5.15.9, v5.15.8, v5.15.7, v5.15.6, v5.15.5, v5.15.4, v5.15.3, v5.15.2, v5.15.1, v5.15, v5.14.14, v5.14.13, v5.14.12, v5.14.11, v5.14.10, v5.14.9, v5.14.8, v5.14.7, v5.14.6, v5.10.67, v5.10.66, v5.14.5, v5.14.4, v5.10.65, v5.14.3, v5.10.64, v5.14.2, v5.10.63, v5.14.1, v5.10.62, v5.14, v5.10.61, v5.10.60, v5.10.53, v5.10.52, v5.10.51, v5.10.50, v5.10.49, v5.13, v5.10.46, v5.10.43, v5.10.42, v5.10.41, v5.10.40, v5.10.39, v5.4.119, v5.10.36, v5.10.35, v5.10.34, v5.4.116, v5.10.33, v5.12, v5.10.32, v5.10.31, v5.10.30, v5.10.27, v5.10.26, v5.10.25, v5.10.24, v5.10.23, v5.10.22, v5.10.21, v5.10.20, v5.10.19, v5.4.101, v5.10.18, v5.10.17, v5.11, v5.10.16, v5.10.15, v5.10.14, v5.10, v5.8.17, v5.8.16, v5.8.15, v5.9, v5.8.14, v5.8.13, v5.8.12, v5.8.11, v5.8.10, v5.8.9, v5.8.8, v5.8.7, v5.8.6, v5.4.62, v5.8.5, v5.8.4, v5.4.61, v5.8.3, v5.4.60, v5.8.2, v5.4.59, v5.8.1, v5.4.58, v5.4.57, v5.4.56, v5.8, v5.7.12, v5.4.55, v5.7.11, v5.4.54, v5.7.10, v5.4.53, v5.4.52, v5.7.9, v5.7.8, v5.4.51, v5.4.50, v5.7.7, v5.4.49, v5.7.6 |
|
| #
e93b327d |
| 23-Jun-2020 |
Vincent Chen <vincent.chen@sifive.com> |
riscv: Add extern declarations for vDSO time-related functions
Add extern declarations for vDSO time-related functions to notify the
compiler these functions will be used in somewhere to
riscv: Add extern declarations for vDSO time-related functions
Add extern declarations for vDSO time-related functions to notify the
compiler these functions will be used in somewhere to avoid
"no previous prototype" compile warning.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
show more ...
|
|
Revision tags: v5.7.5, v5.4.48, v5.7.4, v5.7.3, v5.4.47, v5.4.46, v5.7.2 |
|
| #
ad5d1122 |
| 09-Jun-2020 |
Vincent Chen <vincent.chen@sifive.com> |
riscv: use vDSO common flow to reduce the latency of the time-related functions
Even if RISC-V has supported the vDSO feature, the latency of the functions
for obtaining the system time
riscv: use vDSO common flow to reduce the latency of the time-related functions
Even if RISC-V has supported the vDSO feature, the latency of the functions
for obtaining the system time is still expensive. It is because these
functions still trigger a corresponding system call in the process, which
slows down the response time. If we want to remove the system call to
reduce the latency, the kernel should have the ability to output the system
clock information to userspace. This patch introduces the vDSO common flow
to enable the kernel to achieve the above feature and uses "rdtime"
instruction to obtain the current time in the user space. Under this
condition, the latency cost by the ecall from U-mode to S-mode can be
eliminated. After applying this patch, the latency of gettimeofday()
measured on the HiFive unleashed board can be reduced by %61.
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
show more ...
|