Bug 772637
| Summary: | Generated PNG files are different on various arches | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | Honza Horak <hhorak> |
| Component: | graphviz | Assignee: | Jaroslav Škarvada <jskarvad> |
| Status: | CLOSED ERRATA | QA Contact: | Miroslav Hradílek <mhradile> |
| Severity: | unspecified | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | 6.2 | CC: | azelinka, tpelka |
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | graphviz-2.26.0-8.el6 | Doc Type: | Bug Fix |
| Doc Text: |
Previously dot could generate different images on i386 and x86_64 architectures, which could lead to multilib conflicts for packages that use graphviz during its build process. The problem was caused by i386 FPU. It's registers are wider than C double type and if compiled with -O2 more arithmetic is done in FPU registers. The error increases which finally could lead to round/trunc error and shift in output images. Now the code is compiled with -ffloat-store compiler flag on i386 and intermediate results are not stored in FPU registers. Also the -ffast-math compiler flag was removed, because the performance benefit is very low, but it could cause a lot of hard to debug problems.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2012-09-19 10:17:45 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
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Description
Honza Horak
2012-01-09 13:44:18 UTC
This request was evaluated by Red Hat Product Management for inclusion in the current release of Red Hat Enterprise Linux. Because the affected component is not scheduled to be updated in the current release, Red Hat is unfortunately unable to address this request at this time. Red Hat invites you to ask your support representative to propose this request, if appropriate and relevant, in the next release of Red Hat Enterprise Linux. If you would like it considered as an exception in the current release, please ask your support representative. it's a bug in graphviz, doxygen calls graphviz tools to create the png files. A workaround for libisofs is to set HAVE_DOT= no in doxygen.conf.in to not use dot from graphviz. Analysis of this problem written in Bug 827927 comment 5.
Technical note added. If any revisions are required, please edit the "Technical Notes" field
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New Contents:
Previously dot could generate different images on i386 and x86_64 architectures, which could lead to multilib conflicts for packages that use graphviz during its build process. The problem was caused by i386 FPU. It's registers are wider than C double type and if compiled with -O2 more arithmetic is done in FPU registers. The error increases which finally could lead to round/trunc error and shift in output images. Now the code is compiled with -ffloat-store compiler flag on i386 and intermediate results are not stored in FPU registers. Also the -ffast-math compiler flag was removed, because the performance benefit is very low, but it could cause a lot of hard to debug problems.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHBA-2012-1291.html |