From owner-dev-commits-src-main@freebsd.org Mon Feb 8 10:48:26 2021 Return-Path: Delivered-To: dev-commits-src-main@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 336B752D37D; Mon, 8 Feb 2021 10:48:26 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4DZ2n52sTzz3HHk; Mon, 8 Feb 2021 10:48:24 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 1BA0716375; Mon, 8 Feb 2021 10:48:24 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 118AmNe7004236; Mon, 8 Feb 2021 10:48:23 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 118AmNMF004235; Mon, 8 Feb 2021 10:48:23 GMT (envelope-from git) Date: Mon, 8 Feb 2021 10:48:23 GMT Message-Id: <202102081048.118AmNMF004235@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Edward Tomasz Napierala Subject: git: fb8c2f743ab6 - main - arm64: optimize set_syscall_retval() MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: trasz X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: fb8c2f743ab695f6004650b58bf96972e2535b20 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-main@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for the main branch of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Feb 2021 10:48:26 -0000 The branch main has been updated by trasz: URL: https://cgit.FreeBSD.org/src/commit/?id=fb8c2f743ab695f6004650b58bf96972e2535b20 commit fb8c2f743ab695f6004650b58bf96972e2535b20 Author: Edward Tomasz Napierala AuthorDate: 2021-02-08 10:46:29 +0000 Commit: Edward Tomasz Napierala 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;