On 2022/10/31 23:04, Leizhen (ThunderTown) wrote: > Now, we need to make a decision. Choose one of the two: > 1. Continue with my current approach. Improve the average performance of > kallsyms_lookup_name() by 20 to 30 times. The memory overhead is increased by: > arm64 (defconfig): > 73.5KiB and 4.0% if CONFIG_KALLSYMS_ALL=y. > 19.8KiB and 2.8% if CONFIG_KALLSYMS_ALL=n. > x86 (defconfig): > 49.0KiB and 3.0% if CONFIG_KALLSYMS_ALL=y. > 16.8KiB and 2.3% if CONFIG_KALLSYMS_ALL=n. > 2. Sort names, binary search (The static function causes duplicate names. Additional work is required） > 2^18=262144, only up to 18 symbol expansions and comparisons are required. > The performance is definitely excellent, although I haven't tested it yet. > The memory overhead is increased by: 6 * kallsyms_num_syms > arm64 (defconfig): > 1MiB if CONFIG_KALLSYMS_ALL=y. > 362KiB if CONFIG_KALLSYMS_ALL=n. > x86 (defconfig): > 770KiB if CONFIG_KALLSYMS_ALL=y. > 356KiB if CONFIG_KALLSYMS_ALL=n. Hi, Luis: I've implemented v8 based on method 2(Sort names, binary search). The memory overhead is increased by: 3 * kallsyms_num_syms. kallsyms_offsets_of_names[] is not added in v8 because it does not help much in performance improvement, so save (3 * kallsyms_num_syms) bytes. For details about the performance data, please see the commit message. -- Regards, Zhen Lei
