From owner-svn-src-all@freebsd.org Thu Oct 29 15:36:21 2020 Return-Path: Delivered-To: svn-src-all@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 AD5294554DF; Thu, 29 Oct 2020 15:36:21 +0000 (UTC) (envelope-from trasz@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 "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4CMV0P3YQSz3fjs; Thu, 29 Oct 2020 15:36:21 +0000 (UTC) (envelope-from trasz@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 5D6212FB46; Thu, 29 Oct 2020 15:36:21 +0000 (UTC) (envelope-from trasz@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 09TFaLiJ030974; Thu, 29 Oct 2020 15:36:21 GMT (envelope-from trasz@FreeBSD.org) Received: (from trasz@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 09TFaLX3030973; Thu, 29 Oct 2020 15:36:21 GMT (envelope-from trasz@FreeBSD.org) Message-Id: <202010291536.09TFaLX3030973@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: trasz set sender to trasz@FreeBSD.org using -f From: Edward Tomasz Napierala Date: Thu, 29 Oct 2020 15:36:21 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r367138 - head/sys/riscv/riscv X-SVN-Group: head X-SVN-Commit-Author: trasz X-SVN-Commit-Paths: head/sys/riscv/riscv X-SVN-Commit-Revision: 367138 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 29 Oct 2020 15:36:21 -0000 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;