6271 dtrace caused excessive fork time
Author: Bryan Cantrill <bryan@joyent.com> Reviewed by: Adam Leventhal <ahl@delphix.com> Reviewed by: Dan McDonald <danmcd@omniti.com> Reviewed by: Richard Lowe <richlowe@richlowe.net> Approved by: Gordon Ross <gwr@nexenta.com> illumos/illumos-gate@7bd3c1d12d
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2020-12-20 02:59:44 +00:00
svn path=/vendor-sys/illumos/dist/; revision=289003
99
cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh
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cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh
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#
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# This file and its contents are supplied under the terms of the
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# Common Development and Distribution License ("CDDL"), version 1.0.
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# You may only use this file in accordance with the terms of version
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# 1.0 of the CDDL.
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#
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# A full copy of the text of the CDDL should have accompanied this
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# source. A copy of the CDDL is also available via the Internet at
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# http://www.illumos.org/license/CDDL.
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#
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#
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# Copyright (c) 2015, Joyent, Inc. All rights reserved.
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#
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#
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# This test assures that we can have the same provider name across multiple
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# probe definitions, and that the result will be the union of those
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# definitions. In particular, libusdt depends on this when (for example)
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# node modules that create a provider are loaded multiple times due to
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# being included by different modules.
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#
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if [ $# != 1 ]; then
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echo expected one argument: '<'dtrace-path'>'
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exit 2
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fi
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dtrace=$1
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DIR=/var/tmp/dtest.$$
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mkdir $DIR
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cd $DIR
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cat > test.c <<EOF
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#include <unistd.h>
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void
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main()
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{
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EOF
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objs=
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for oogle in bagnoogle stalloogle cockoogle; do
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cat > $oogle.c <<EOF
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#include <sys/sdt.h>
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void
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$oogle()
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{
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DTRACE_PROBE(doogle, $oogle);
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}
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EOF
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cat > $oogle.d <<EOF
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provider doogle {
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probe $oogle();
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};
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EOF
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gcc -m32 -c $oogle.c
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if [ $? -ne 0 ]; then
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print -u2 "failed to compile $oogle.c"
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exit 1
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fi
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$dtrace -G -32 -s $oogle.d $oogle.o -o $oogle.d.o
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if [ $? -ne 0 ]; then
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print -u2 "failed to process $oogle.d"
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exit 1
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fi
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objs="$objs $oogle.o $oogle.d.o"
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echo $oogle'();' >> test.c
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done
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echo "}" >> test.c
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gcc -m32 -o test test.c $objs
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if [ $? -ne 0 ]; then
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print -u2 "failed to compile test.c"
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exit 1
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fi
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$dtrace -n 'doogle$target:::{@[probename] = count()}' \
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-n 'END{printa("%-10s %@d\n", @)}' -x quiet -x aggsortkey -Zc ./test
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if [ $? -ne 0 ]; then
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print -u2 "failed to execute test"
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exit 1
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fi
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cd /
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/usr/bin/rm -rf $DIR
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exit 0
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@ -0,0 +1,4 @@
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bagnoogle 1
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cockoogle 1
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stalloogle 1
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@ -14809,8 +14809,8 @@ dtrace_helper_provider_add(dof_helper_t *dofhp, int gen)
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* Check to make sure this isn't a duplicate.
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*/
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for (i = 0; i < help->dthps_nprovs; i++) {
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if (dofhp->dofhp_dof ==
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help->dthps_provs[i]->dthp_prov.dofhp_dof)
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if (dofhp->dofhp_addr ==
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help->dthps_provs[i]->dthp_prov.dofhp_addr)
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return (EALREADY);
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}
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@ -15162,7 +15162,14 @@ dtrace_helper_slurp(dof_hdr_t *dof, dof_helper_t *dhp)
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dtrace_enabling_destroy(enab);
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if (dhp != NULL && nprovs > 0) {
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/*
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* Now that this is in-kernel, we change the sense of the
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* members: dofhp_dof denotes the in-kernel copy of the DOF
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* and dofhp_addr denotes the address at user-level.
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*/
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dhp->dofhp_addr = dhp->dofhp_dof;
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dhp->dofhp_dof = (uint64_t)(uintptr_t)dof;
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if (dtrace_helper_provider_add(dhp, gen) == 0) {
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mutex_exit(&dtrace_lock);
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dtrace_helper_provider_register(curproc, help, dhp);
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@ -1784,6 +1784,18 @@ fasttrap_meta_provide(void *arg, dtrace_helper_provdesc_t *dhpv, pid_t pid)
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return (provider);
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}
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/*
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* We know a few things about our context here: we know that the probe being
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* created doesn't already exist (DTrace won't load DOF at the same address
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* twice, even if explicitly told to do so) and we know that we are
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* single-threaded with respect to the meta provider machinery. Knowing that
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* this is a new probe and that there is no way for us to race with another
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* operation on this provider allows us an important optimization: we need not
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* lookup a probe before adding it. Saving this lookup is important because
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* this code is in the fork path for processes with USDT probes, and lookups
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* here are potentially very expensive because of long hash conflicts on
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* module, function and name (DTrace doesn't hash on provider name).
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*/
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/*ARGSUSED*/
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static void
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fasttrap_meta_create_probe(void *arg, void *parg,
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@ -1820,19 +1832,6 @@ fasttrap_meta_create_probe(void *arg, void *parg,
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return;
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}
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/*
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* Grab the creation lock to ensure consistency between calls to
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* dtrace_probe_lookup() and dtrace_probe_create() in the face of
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* other threads creating probes.
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*/
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mutex_enter(&provider->ftp_cmtx);
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if (dtrace_probe_lookup(provider->ftp_provid, dhpb->dthpb_mod,
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dhpb->dthpb_func, dhpb->dthpb_name) != 0) {
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mutex_exit(&provider->ftp_cmtx);
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return;
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}
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ntps = dhpb->dthpb_noffs + dhpb->dthpb_nenoffs;
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ASSERT(ntps > 0);
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@ -1840,7 +1839,6 @@ fasttrap_meta_create_probe(void *arg, void *parg,
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if (fasttrap_total > fasttrap_max) {
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atomic_add_32(&fasttrap_total, -ntps);
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mutex_exit(&provider->ftp_cmtx);
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return;
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}
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@ -1904,8 +1902,6 @@ fasttrap_meta_create_probe(void *arg, void *parg,
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*/
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pp->ftp_id = dtrace_probe_create(provider->ftp_provid, dhpb->dthpb_mod,
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dhpb->dthpb_func, dhpb->dthpb_name, FASTTRAP_OFFSET_AFRAMES, pp);
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mutex_exit(&provider->ftp_cmtx);
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}
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/*ARGSUSED*/
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*
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* 1.2.4 Caller's context
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*
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* dtms_create_probe() is called from either ioctl() or module load context.
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* The DTrace framework is locked in such a way that meta providers may not
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* register or unregister. This means that the meta provider cannot call
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* dtrace_meta_register() or dtrace_meta_unregister(). However, the context is
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* such that the provider may (and is expected to) call provider-related
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* DTrace provider APIs including dtrace_probe_create().
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* dtms_create_probe() is called from either ioctl() or module load context
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* in the context of a newly-created provider (that is, a provider that
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* is a result of a call to dtms_provide_pid()). The DTrace framework is
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* locked in such a way that meta providers may not register or unregister,
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* such that no other thread can call into a meta provider operation and that
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* atomicity is assured with respect to meta provider operations across
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* dtms_provide_pid() and subsequent calls to dtms_create_probe().
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* The context is thus effectively single-threaded with respect to the meta
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* provider, and that the meta provider cannot call dtrace_meta_register()
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* or dtrace_meta_unregister(). However, the context is such that the
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* provider may (and is expected to) call provider-related DTrace provider
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* APIs including dtrace_probe_create().
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*
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* 1.3 void *dtms_provide_pid(void *arg, dtrace_meta_provider_t *mprov,
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* pid_t pid)
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