[PATCH v2 0/2] powerpc: Add support for system call vectored
Lucas A. M. Magalhaes
lamm@linux.ibm.com
Tue Dec 8 18:24:29 GMT 2020
Hi Matheus,
Worked on top of Adhemerval's brk patch. But it fails if applied
directly on master.
Tested on a POWER9 with and without scv support.
Tested-by: Lucas A. M. Magalhães <lamm@linux.ibm.com>
Quoting Matheus Castanho via Libc-alpha (2020-12-03 14:15:26)
> This patchset enables the usage of system call vectored (scv) instruction by
> system calls for improved performance on POWER9 and later processors.
>
> This new version dropped the patch to move brk to a C-based implementation, in
> favor of Adhemerval's patch [0]. So it should be applied on top of that.
>
> Also, it modified the scv check mechanism to remove the thread pointer check as
> suggested by Florian. Now the dynamic loader always uses sc, static code still
> checks the thread pointer before accessing the TCB, and shared code (outside the
> dl) accesses the TCB directly.
>
> Please check each patch for more details, specially 1/2 which explains the
> rationale and details of the runtime mechanism to choose between the old
> behavior (sc) and the new one (scv 0).
>
> Tested on powerpc, powerpc64, and powerpc64le (with and without scv)
>
> [0] https://sourceware.org/pipermail/libc-alpha/2020-November/119770.html
>
> ---
>
> v2:
> - Fix typos and comments to match GNU style
> - Remove the check for the thread pointer on shared code, and always use sc
> when inside the dynamic loader
> - Drop the patch implementing brk in C
>
> Matheus Castanho (2):
> powerpc: Runtime selection between sc and scv for syscalls
> powerpc: Use scv instruction on clone when available
>
> sysdeps/powerpc/powerpc32/sysdep.h | 15 ++-
> sysdeps/powerpc/powerpc64/sysdep.h | 120 +++++++++++++++++-
> .../unix/sysv/linux/powerpc/powerpc64/clone.S | 36 +++++-
> .../unix/sysv/linux/powerpc/powerpc64/vfork.S | 6 +-
> sysdeps/unix/sysv/linux/powerpc/syscall.S | 11 +-
> sysdeps/unix/sysv/linux/powerpc/sysdep.h | 93 ++++++++++----
> 6 files changed, 241 insertions(+), 40 deletions(-)
>
> --
> 2.26.2
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