anchao opened a new pull request #3259: URL: https://github.com/apache/incubator-nuttx/pull/3259
## Summary libc/string: Use Byte-Shift algorithm for very long needles Reference here: https://github.com/taleinat/byteshift_strstr Signed-off-by: chao.an <anc...@xiaomi.com> ## Impact ## Testing strstr(3) performance degrade in the case of long needles, (e.g curl/mbedtls parse the CA certificates) CA certificates: https://curl.se/docs/caextract.html curl mbedtls_x509_crt_parse_file: https://github.com/curl/curl/blob/3266b35bbe21c68dea0dc7ccd991eb028e6d360c/lib/vtls/mbedtls.c#L304 strstr: https://github.com/ARMmbed/mbedtls/blob/e93095fe6bdc99818f71197e808d20244cd1e41a/library/x509_crt.c#L1461-L1464 https://github.com/ARMmbed/mbedtls/blob/e93095fe6bdc99818f71197e808d20244cd1e41a/library/pem.c#L246-L251 In the default implementation, curl's CA certificate parse will last about 4 - 4.5 *Seconds* in multiple strstr(3) processing, after optimization, reduced to 80 milliseconds. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
