WIP: Re-add "-fno-rounding-math" and "-fno-signaling-nans" options in JIT #6755
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The above compiler options were removed in eclipse-openj9#4156. Removing the above compiler options causes a performance regression. Symptoms of the performance regression: bursts of high throughput mixed with periods of lower throughput. These symptoms cause a 5-7% throughput regression. Reintroducing the above compiler options fixes the throughput regression. Signed-off-by: Babneet Singh <sbabneet@ca.ibm.com>
babsingh
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There is a lot of discussion in the PR that removed the flags #4156 which says that the -fno-rounding-math and -fno-signaling-nans are default on gcc 4.7 and up - what gcc is causing the problem? Our default GCC should be above where they became default? |
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@andrewcraik The performance issue is still under investigation (WIP). This change caught my eye in the |
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The above compiler options were removed in #4156.
Removing the above compiler options causes a performance regression.
Symptoms of the performance regression: bursts of high throughput mixed
with periods of lower throughput. These symptoms cause a 5-7% throughput
regression.
Reintroducing the above compiler options fixes the throughput
regression.
Signed-off-by: Babneet Singh sbabneet@ca.ibm.com