Date: Mon, 8 Feb 2021 10:48:23 GMT From: Edward Tomasz Napierala <trasz@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: fb8c2f743ab6 - main - arm64: optimize set_syscall_retval() Message-ID: <202102081048.118AmNMF004235@gitrepo.freebsd.org>
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The branch main has been updated by trasz: URL: https://cgit.FreeBSD.org/src/commit/?id=fb8c2f743ab695f6004650b58bf96972e2535b20 commit fb8c2f743ab695f6004650b58bf96972e2535b20 Author: Edward Tomasz Napierala <trasz@FreeBSD.org> AuthorDate: 2021-02-08 10:46:29 +0000 Commit: Edward Tomasz Napierala <trasz@FreeBSD.org> CommitDate: 2021-02-08 10:46:47 +0000 arm64: optimize set_syscall_retval() Microoptimize set_syscall_retval() for arm64 by predicting the return value to be zero. This is similar to what has been done for other architectures Reviewed By: emaste, mhorne Differential Revision: https://reviews.freebsd.org/D26991 --- sys/arm64/arm64/vm_machdep.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/sys/arm64/arm64/vm_machdep.c b/sys/arm64/arm64/vm_machdep.c index 9e9b588c7db1..d4dd32caef06 100644 --- a/sys/arm64/arm64/vm_machdep.c +++ b/sys/arm64/arm64/vm_machdep.c @@ -143,12 +143,14 @@ cpu_set_syscall_retval(struct thread *td, int error) frame = td->td_frame; - switch (error) { - case 0: + if (__predict_true(error == 0)) { frame->tf_x[0] = td->td_retval[0]; frame->tf_x[1] = td->td_retval[1]; frame->tf_spsr &= ~PSR_C; /* carry bit */ - break; + return; + } + + switch (error) { case ERESTART: frame->tf_elr -= 4; break;
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