Youwei Wang has posted comments on this change. Change subject: IMPALA-2809: Improve ByteSwap with builtin function or SSE or AVX2. ......................................................................
Patch Set 5: (1 comment) http://gerrit.cloudera.org:8080/#/c/3081/5/be/src/util/bit-util.inline.h File be/src/util/bit-util.inline.h: Line 139: __attribute__((target("sse4.2"))) > I just realized that I'm not sure if we can use __attribute__((target... an Hi Jim. This issue has been discussed with some other engineers from Cloudera before. The following is my personal understandings: the comment there points out we can't add the "compiler flag", which effects global codebase. And yes, some unwanted SSE code will be generated using the -msse4.2 compiler flag. But this case is different for such attribute since it is only used upon the function containing such SSE code. Hence the binary generation for other code will not change. As for this function ByteSwapSSE_Unit itself, there has been a runtime guard to decide whether to enter this branch according the real-world CPU types. I am not sure whether I have explained this clearly enough. Please feel free to ask any question here if you still feel confused. -- To view, visit http://gerrit.cloudera.org:8080/3081 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: comment Gerrit-Change-Id: I392ed5a8d5683f30f161282c228c1aedd7b648c1 Gerrit-PatchSet: 5 Gerrit-Project: Impala Gerrit-Branch: cdh5-trunk Gerrit-Owner: Youwei Wang <[email protected]> Gerrit-Reviewer: Alex Behm <[email protected]> Gerrit-Reviewer: Jim Apple <[email protected]> Gerrit-Reviewer: Marcel Kornacker <[email protected]> Gerrit-Reviewer: Mostafa Mokhtar <[email protected]> Gerrit-Reviewer: Tim Armstrong <[email protected]> Gerrit-Reviewer: Youwei Wang <[email protected]> Gerrit-HasComments: Yes
