Date: Thu, 29 Oct 2020 15:36:21 +0000 (UTC) From: Edward Tomasz Napierala <trasz@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r367138 - head/sys/riscv/riscv Message-ID: <202010291536.09TFaLX3030973@repo.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: trasz Date: Thu Oct 29 15:36:20 2020 New Revision: 367138 URL: https://svnweb.freebsd.org/changeset/base/367138 Log: Optimize set_syscall_retval for riscv by predicting the return value to be zero. Reviewed by: mhorne, kp MFC after: 2 weeks Sponsored by: EPSRC Differential Revision: https://reviews.freebsd.org/D26990 Modified: head/sys/riscv/riscv/vm_machdep.c Modified: head/sys/riscv/riscv/vm_machdep.c ============================================================================== --- head/sys/riscv/riscv/vm_machdep.c Thu Oct 29 15:28:15 2020 (r367137) +++ head/sys/riscv/riscv/vm_machdep.c Thu Oct 29 15:36:20 2020 (r367138) @@ -132,12 +132,14 @@ cpu_set_syscall_retval(struct thread *td, int error) frame = td->td_frame; - switch (error) { - case 0: + if (__predict_true(error == 0)) { frame->tf_a[0] = td->td_retval[0]; frame->tf_a[1] = td->td_retval[1]; frame->tf_t[0] = 0; /* syscall succeeded */ - break; + return; + } + + switch (error) { case ERESTART: frame->tf_sepc -= 4; /* prev instruction */ break;
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?202010291536.09TFaLX3030973>