From owner-svn-src-head@freebsd.org Sun Oct 22 20:22:25 2017 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 50241E34018; Sun, 22 Oct 2017 20:22:25 +0000 (UTC) (envelope-from mjg@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 mx1.freebsd.org (Postfix) with ESMTPS id 2BA8F73919; Sun, 22 Oct 2017 20:22:25 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id v9MKMO3W043076; Sun, 22 Oct 2017 20:22:24 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id v9MKMOjX043073; Sun, 22 Oct 2017 20:22:24 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <201710222022.v9MKMOjX043073@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Sun, 22 Oct 2017 20:22:24 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r324869 - in head/sys: cddl/dev/sdt kern sys X-SVN-Group: head X-SVN-Commit-Author: mjg X-SVN-Commit-Paths: in head/sys: cddl/dev/sdt kern sys X-SVN-Commit-Revision: 324869 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 22 Oct 2017 20:22:25 -0000 Author: mjg Date: Sun Oct 22 20:22:23 2017 New Revision: 324869 URL: https://svnweb.freebsd.org/changeset/base/324869 Log: sdt: make all sdt probe sites test one variable This saves on cache misses at the expense of a slight grow of .text. Note this is a bandaid for lack of hotpatching. Discussed with: markj Modified: head/sys/cddl/dev/sdt/sdt.c head/sys/kern/kern_sdt.c head/sys/sys/sdt.h Modified: head/sys/cddl/dev/sdt/sdt.c ============================================================================== --- head/sys/cddl/dev/sdt/sdt.c Sun Oct 22 20:22:11 2017 (r324868) +++ head/sys/cddl/dev/sdt/sdt.c Sun Oct 22 20:22:23 2017 (r324869) @@ -76,6 +76,8 @@ static void sdt_kld_unload_try(void *, struct linker_f static MALLOC_DEFINE(M_SDT, "SDT", "DTrace SDT providers"); +static int sdt_probes_enabled_count; + static dtrace_pattr_t sdt_attr = { { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON }, { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN }, @@ -208,6 +210,9 @@ sdt_enable(void *arg __unused, dtrace_id_t id, void *p probe->sdtp_lf->nenabled++; if (strcmp(probe->prov->name, "lockstat") == 0) lockstat_enabled++; + sdt_probes_enabled_count++; + if (sdt_probes_enabled_count == 1) + sdt_probes_enabled = true; } static void @@ -217,6 +222,9 @@ sdt_disable(void *arg __unused, dtrace_id_t id, void * KASSERT(probe->sdtp_lf->nenabled > 0, ("no probes enabled")); + sdt_probes_enabled_count--; + if (sdt_probes_enabled_count == 0) + sdt_probes_enabled = false; if (strcmp(probe->prov->name, "lockstat") == 0) lockstat_enabled--; probe->id = 0; Modified: head/sys/kern/kern_sdt.c ============================================================================== --- head/sys/kern/kern_sdt.c Sun Oct 22 20:22:11 2017 (r324868) +++ head/sys/kern/kern_sdt.c Sun Oct 22 20:22:23 2017 (r324869) @@ -37,6 +37,7 @@ SDT_PROVIDER_DEFINE(sdt); * dtrace_probe() when it loads. */ sdt_probe_func_t sdt_probe_func = sdt_probe_stub; +volatile bool __read_frequently sdt_probes_enabled; /* * This is a stub for probe calls in case kernel DTrace support isn't Modified: head/sys/sys/sdt.h ============================================================================== --- head/sys/sys/sdt.h Sun Oct 22 20:22:11 2017 (r324868) +++ head/sys/sys/sdt.h Sun Oct 22 20:22:23 2017 (r324869) @@ -80,6 +80,8 @@ #include #include +extern volatile bool sdt_probes_enabled; + #ifndef KDTRACE_HOOKS #define SDT_PROVIDER_DEFINE(prov) @@ -161,10 +163,12 @@ SET_DECLARE(sdt_argtypes_set, struct sdt_argtype); extern struct sdt_probe sdt_##prov##_##mod##_##func##_##name[1] #define SDT_PROBE(prov, mod, func, name, arg0, arg1, arg2, arg3, arg4) do { \ - if (__predict_false(sdt_##prov##_##mod##_##func##_##name->id)) \ + if (__predict_false(sdt_probes_enabled)) { \ + if (__predict_false(sdt_##prov##_##mod##_##func##_##name->id)) \ (*sdt_probe_func)(sdt_##prov##_##mod##_##func##_##name->id, \ (uintptr_t) arg0, (uintptr_t) arg1, (uintptr_t) arg2, \ (uintptr_t) arg3, (uintptr_t) arg4); \ + } \ } while (0) #define SDT_PROBE_ARGTYPE(prov, mod, func, name, num, type, xtype) \