c77b926c9d
* Fri Jan 14 2022 Florian Weimer <fweimer@redhat.com> - 2.34-19 - Optionally accelerate sched_getcpu using rseq (#2024347) Resolves: #2024347
43 lines
1.5 KiB
Diff
43 lines
1.5 KiB
Diff
Downstream-only patch to disable rseq by default. This is necessary
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because CRIU does not yet support rseq:
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criu: Implement rseq support
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<https://bugzilla.redhat.com/show_bug.cgi?id=2033446>
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diff --git a/manual/tunables.texi b/manual/tunables.texi
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index 28ff502990c2a10f..f559c44dcec4624b 100644
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--- a/manual/tunables.texi
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+++ b/manual/tunables.texi
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@@ -425,11 +425,13 @@ The value is measured in bytes. The default is @samp{41943040}
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@end deftp
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@deftp Tunable glibc.pthread.rseq
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-The @code{glibc.pthread.rseq} tunable can be set to @samp{0}, to disable
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-restartable sequences support in @theglibc{}. This enables applications
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-to perform direct restartable sequence registration with the kernel.
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-The default is @samp{1}, which means that @theglibc{} performs
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-registration on behalf of the application.
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+The @code{glibc.pthread.rseq} tunable can be set to @samp{1}, to enable
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+restartable sequences support. @Theglibc{} uses this to optimize the
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+@code{sched_getcpu} function.
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+
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+The default is @samp{0}, which means that applications can perform
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+restartable sequences registration, but @code{sched_getcpu} is not
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+accelerated.
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Restartable sequences are a Linux-specific extension.
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@end deftp
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diff --git a/sysdeps/nptl/dl-tunables.list b/sysdeps/nptl/dl-tunables.list
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index d24f4be0d08ba407..df2a39ce01858d3b 100644
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--- a/sysdeps/nptl/dl-tunables.list
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+++ b/sysdeps/nptl/dl-tunables.list
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@@ -31,7 +31,7 @@ glibc {
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type: INT_32
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minval: 0
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maxval: 1
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- default: 1
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+ default: 0
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}
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}
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}
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