| Message ID | 20220909130016.727-1-thunder.leizhen@huawei.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | kallsyms: Optimizes the performance of lookup symbols | expand |
Hi, everybody: Can anyone review it? Maybe I should split this patch series into two parts: kallsyms and livepatch. In fact, the performance can be improved even if the compression policy of the symbol type is not changed, that is, the scripts/callsyms.c file is not modified, but we perform the len-based filtering first. That way, it'll be easier for everyone to review. OK, I'm ready for v3. On 2022/9/9 21:00, Zhen Lei wrote: > v1 --> v2: > Add self-test facility > > v1: > Currently, to search for a symbol, we need to expand the symbols in > 'kallsyms_names' one by one, and then use the expanded string for > comparison. This is very slow. > > In fact, we can first compress the name being looked up and then use > it for comparison when traversing 'kallsyms_names'. > > This patch series optimizes the performance of function kallsyms_lookup_name(), > and function klp_find_object_symbol() in the livepatch module. Based on the > test results, the performance overhead is reduced to 5%. That is, the > performance of these functions is improved by 20 times. > > To avoid increasing the kernel size in non-debug mode, the optimization is only > for the case CONFIG_KALLSYMS_ALL=y. > > Zhen Lei (8): > scripts/kallsyms: don't compress symbol type when > CONFIG_KALLSYMS_ALL=y > scripts/kallsyms: rename build_initial_tok_table() > kallsyms: Adjust the types of some local variables > kallsyms: Improve the performance of kallsyms_lookup_name() > kallsyms: Add helper kallsyms_on_each_match_symbol() > livepatch: Use kallsyms_on_each_match_symbol() to improve performance > livepatch: Improve the search performance of > module_kallsyms_on_each_symbol() > kallsyms: Add self-test facility > > include/linux/kallsyms.h | 8 ++ > init/Kconfig | 13 ++ > kernel/Makefile | 1 + > kernel/kallsyms.c | 135 ++++++++++++++++++++- > kernel/kallsyms_selftest.c | 243 +++++++++++++++++++++++++++++++++++++ > kernel/livepatch/core.c | 25 +++- > kernel/module/kallsyms.c | 13 +- > scripts/kallsyms.c | 19 ++- > 8 files changed, 441 insertions(+), 16 deletions(-) > create mode 100644 kernel/kallsyms_selftest.c >
On 2022/9/16 9:27, Leizhen (ThunderTown) wrote: > Hi, everybody: > Can anyone review it? Maybe I should split this patch series > into two parts: kallsyms and livepatch. > In fact, the performance can be improved even if the compression policy > of the symbol type is not changed, that is, the scripts/callsyms.c file is > not modified, but we perform the len-based filtering first. That way, it'll > be easier for everyone to review. OK, I'm ready for v3. Sorry, I didn't sleep well yesterday. The length is the length of the compressed string. Therefore, the solution is not feasible. > > > On 2022/9/9 21:00, Zhen Lei wrote: >> v1 --> v2: >> Add self-test facility >> >> v1: >> Currently, to search for a symbol, we need to expand the symbols in >> 'kallsyms_names' one by one, and then use the expanded string for >> comparison. This is very slow. >> >> In fact, we can first compress the name being looked up and then use >> it for comparison when traversing 'kallsyms_names'. >> >> This patch series optimizes the performance of function kallsyms_lookup_name(), >> and function klp_find_object_symbol() in the livepatch module. Based on the >> test results, the performance overhead is reduced to 5%. That is, the >> performance of these functions is improved by 20 times. >> >> To avoid increasing the kernel size in non-debug mode, the optimization is only >> for the case CONFIG_KALLSYMS_ALL=y. >> >> Zhen Lei (8): >> scripts/kallsyms: don't compress symbol type when >> CONFIG_KALLSYMS_ALL=y >> scripts/kallsyms: rename build_initial_tok_table() >> kallsyms: Adjust the types of some local variables >> kallsyms: Improve the performance of kallsyms_lookup_name() >> kallsyms: Add helper kallsyms_on_each_match_symbol() >> livepatch: Use kallsyms_on_each_match_symbol() to improve performance >> livepatch: Improve the search performance of >> module_kallsyms_on_each_symbol() >> kallsyms: Add self-test facility >> >> include/linux/kallsyms.h | 8 ++ >> init/Kconfig | 13 ++ >> kernel/Makefile | 1 + >> kernel/kallsyms.c | 135 ++++++++++++++++++++- >> kernel/kallsyms_selftest.c | 243 +++++++++++++++++++++++++++++++++++++ >> kernel/livepatch/core.c | 25 +++- >> kernel/module/kallsyms.c | 13 +- >> scripts/kallsyms.c | 19 ++- >> 8 files changed, 441 insertions(+), 16 deletions(-) >> create mode 100644 kernel/kallsyms_selftest.c >> >
v1 --> v2: Add self-test facility v1: Currently, to search for a symbol, we need to expand the symbols in 'kallsyms_names' one by one, and then use the expanded string for comparison. This is very slow. In fact, we can first compress the name being looked up and then use it for comparison when traversing 'kallsyms_names'. This patch series optimizes the performance of function kallsyms_lookup_name(), and function klp_find_object_symbol() in the livepatch module. Based on the test results, the performance overhead is reduced to 5%. That is, the performance of these functions is improved by 20 times. To avoid increasing the kernel size in non-debug mode, the optimization is only for the case CONFIG_KALLSYMS_ALL=y. Zhen Lei (8): scripts/kallsyms: don't compress symbol type when CONFIG_KALLSYMS_ALL=y scripts/kallsyms: rename build_initial_tok_table() kallsyms: Adjust the types of some local variables kallsyms: Improve the performance of kallsyms_lookup_name() kallsyms: Add helper kallsyms_on_each_match_symbol() livepatch: Use kallsyms_on_each_match_symbol() to improve performance livepatch: Improve the search performance of module_kallsyms_on_each_symbol() kallsyms: Add self-test facility include/linux/kallsyms.h | 8 ++ init/Kconfig | 13 ++ kernel/Makefile | 1 + kernel/kallsyms.c | 135 ++++++++++++++++++++- kernel/kallsyms_selftest.c | 243 +++++++++++++++++++++++++++++++++++++ kernel/livepatch/core.c | 25 +++- kernel/module/kallsyms.c | 13 +- scripts/kallsyms.c | 19 ++- 8 files changed, 441 insertions(+), 16 deletions(-) create mode 100644 kernel/kallsyms_selftest.c