Ticket #5284 (closed defect: fixed)
[with patch, positive review] Set sage-flags.txt up to SSE2 only when building Sage in SSE2 only mode/remove SSSE3 and SSE4 flags (followup to #5219)
| Reported by: | mabshoff | Owned by: | mabshoff |
|---|---|---|---|
| Priority: | blocker | Milestone: | sage-3.4.1 |
| Component: | distribution | Keywords: | |
| Cc: | Work issues: | ||
| Report Upstream: | Reviewers: | ||
| Authors: | Merged in: | ||
| Dependencies: | Stopgaps: |
Description (last modified by mabshoff) (diff)
This is a followup to #5219:
- When building ATLAS in SSE2 only mode the sage-flags should be set accordingly to avoid that Sage complains on startup.
- We do not use any SSE instructions beyond PNI (i.e. SSE3) at the moment, yet we check for SSSE3 and SSE4 flags. So do not add them to sage-flags since they will trigger wrong warning.
- Document SAGE_SIMD_MODE in README.txt
Cheers,
Michael
Attachments
-
trac_5284.patch
(958 bytes) -
added by mabshoff 4 years ago.
Change History
comment:2 Changed 4 years ago by mabshoff
- Milestone changed from sage-3.4 to sage-3.4.1
Better luck in 3.4.1.
Cheers,
Michael
comment:4 Changed 4 years ago by mabshoff
- Milestone changed from sage-3.4.2 to sage-3.4.1
This needs to be fixed in 3.4.1!
Cheers,
Michael
comment:5 Changed 4 years ago by mabshoff
We need to check
SAGE_SIMD_MODE
The only supported value at the moment is SSE2. So remove pni, ssse3 from the flags array.
Cheers,
Michael
comment:7 Changed 4 years ago by mabshoff
- Summary changed from Set sage-flags.txt up to SSE2 only when building Sage in SSE2 only mode/remove SSSE3 and SSE4 flags (followup to #5219) to [with patch, needs review] Set sage-flags.txt up to SSE2 only when building Sage in SSE2 only mode/remove SSSE3 and SSE4 flags (followup to #5219)
comment:8 Changed 4 years ago by tornaria
- Summary changed from [with patch, needs review] Set sage-flags.txt up to SSE2 only when building Sage in SSE2 only mode/remove SSSE3 and SSE4 flags (followup to #5219) to [with patch, positive review] Set sage-flags.txt up to SSE2 only when building Sage in SSE2 only mode/remove SSSE3 and SSE4 flags (followup to #5219)
Looks good to me.
For the record, I want to point out that mpir may be using lahf flag, which is not among the tested-for flags. Note that lahf does not depend on ssse3 (e.g. a Pentium D 930 has lahf but not ssse3). Apparently the first intel 64 bit cpus did not have lahf.
comment:9 follow-up: ↓ 10 Changed 4 years ago by was
I also tried this and it works fine.
tornaria -- good catch regarding lahf. We need to make a ticket about that!!
comment:10 in reply to: ↑ 9 Changed 4 years ago by mabshoff
Replying to was:
I also tried this and it works fine.
tornaria -- good catch regarding lahf. We need to make a ticket about that!!
That is part of #5849.
A P4 that does not have lahf is exceedingly rare and AFAIK we have never seen a problem with it, but I am sure we will hit it in the future. Note that x86 vs. core2 code in 64 bit MPIR is quote noticeable performance wise for some benchmarks.
Cheers,
Michael
comment:11 Changed 4 years ago by mabshoff
- Status changed from assigned to closed
- Resolution set to fixed
Merged in Sage 3.4.1.final. Last ticket for 3.4.1 - w00000t.
Cheers,
Michael
