Re: glibc qsort() vulnerability
От | Nathan Bossart |
---|---|
Тема | Re: glibc qsort() vulnerability |
Дата | |
Msg-id | 20240208015211.GA445153@nathanxps13 обсуждение исходный текст |
Ответ на | Re: glibc qsort() vulnerability (Andres Freund <andres@anarazel.de>) |
Ответы |
Re: glibc qsort() vulnerability
Re: glibc qsort() vulnerability |
Список | pgsql-hackers |
On Wed, Feb 07, 2024 at 04:42:07PM -0800, Andres Freund wrote: > On 2024-02-07 16:21:24 -0600, Nathan Bossart wrote: >> The assembly for that looks encouraging, but I still need to actually test >> it... > > Possible. For 16bit upcasting to 32bit is clearly the best way. For 32 bit > that doesn't work, given the 32bit return, so we need something more. For the same compASC() test, I see an ~8.4% improvement with your int64 code and a ~3.4% improvement with this: int compASC(const void *a, const void *b) { int result; if (unlikely(pg_sub_s32_overflow(*(const int32 *) a, *(const int32 *) b, &result))) { if (*(const int32 *) a > *(const int32 *) b) return 1; if (*(const int32 *) a < *(const int32 *) b) return -1; return 0; } return result; } -- Nathan Bossart Amazon Web Services: https://aws.amazon.com
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