科技回声

5 条评论

zbjornson超过 6 年前

v8 (before v5.9) used to only inline functions that were under 600 characters (and 196 AST nodes). That was another fun way to add fuel to the tab vs. spaces fire: identical functions that used spaces instead of tabs could run significantly slower because they weren't inlined.

评论 #18170726 未加载

ndesaulniers超过 6 年前

__builtin_constant_p is a rats nest of edge cases. We're looking into differences between implementation from gcc and clang now for the kernel.

评论 #18172009 未加载

rurban超过 6 年前

I'd really like to see a comparison with clang's inliner. In my cases [1] gcc constexpr support was always horrible and clang decent. So I'm not sure if using the builtin assembler would fix the gcc situation.1: <a href="https://github.com/rurban/safeclib/blob/master/tests/perf_memcpy_s.c" rel="nofollow">https://github.com/rurban/safeclib/blob/master/tests/perf_me...</a>

评论 #18182028 未加载

amelius超过 6 年前

Seems like those competitions where people write one-liners have their merits.

评论 #18173130 未加载

评论 #18172129 未加载

jwilk超过 6 年前

Ugh, all external links in this article go through the Google click tracker. :-/Here are ungoogled URLs:<a href="https://elixir.bootlin.com/linux/v4.17/source/include/linux/jhash.h#L70" rel="nofollow">https://elixir.bootlin.com/linux/v4.17/source/include/linux/...</a><a href="https://elixir.bootlin.com/linux/v4.17/source/include/net/dst.h#L442" rel="nofollow">https://elixir.bootlin.com/linux/v4.17/source/include/net/ds...</a><a href="https://elixir.bootlin.com/linux/v4.17/source/include/linux/thread_info.h#L121" rel="nofollow">https://elixir.bootlin.com/linux/v4.17/source/include/linux/...</a><a href="https://c9x.me/x86/html/file_module_x86_id_318.html" rel="nofollow">https://c9x.me/x86/html/file_module_x86_id_318.html</a><a href="https://elixir.bootlin.com/linux/v4.17/source/arch/x86/include/asm/bug.h#L33" rel="nofollow">https://elixir.bootlin.com/linux/v4.17/source/arch/x86/inclu...</a><a href="https://gcc.gnu.org/onlinedocs/gcc-4.0.1/gcc/Extended-Asm.html" rel="nofollow">https://gcc.gnu.org/onlinedocs/gcc-4.0.1/gcc/Extended-Asm.ht...</a><a href="https://www.embecosm.com/appnotes/ean10/ean10-howto-llvmas-1.0.html#idp109760" rel="nofollow">https://www.embecosm.com/appnotes/ean10/ean10-howto-llvmas-1...</a><a href="https://patchwork.kernel.org/patch/10450037/" rel="nofollow">https://patchwork.kernel.org/patch/10450037/</a><a href="https://lkml.org/lkml/2018/10/4/25" rel="nofollow">https://lkml.org/lkml/2018/10/4/25</a><a href="https://elixir.bootlin.com/linux/v4.17/source/include/linux/slab.h#L699" rel="nofollow">https://elixir.bootlin.com/linux/v4.17/source/include/linux/...</a><a href="https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html" rel="nofollow">https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html</a><a href="https://elixir.bootlin.com/linux/v4.17/source/arch/x86/kvm/vmx.c#L9669" rel="nofollow">https://elixir.bootlin.com/linux/v4.17/source/arch/x86/kvm/v...</a><a href="https://elixir.bootlin.com/linux/v4.17/source/arch/x86/kvm/vmx.c#L706" rel="nofollow">https://elixir.bootlin.com/linux/v4.17/source/arch/x86/kvm/v...</a>

评论 #18170285 未加载

评论 #18178086 未加载

5 条评论

zbjornson超过 6 年前

评论 #18170726 未加载

ndesaulniers超过 6 年前

__builtin_constant_p is a rats nest of edge cases. We're looking into differences between implementation from gcc and clang now for the kernel.

How newlines affect Linux kernel performance

5 条评论

How newlines affect Linux kernel performance

5 条评论