svn commit: r291963 - in head: cddl/contrib/opensolaris/cmd/dtrace/test/tst/common/usdt sys/cddl/contrib/opensolaris/uts/common/dtrace sys/cddl/contrib/opensolaris/uts/common/sys
Mark Johnston
markj at FreeBSD.org
Mon Dec 7 21:49:35 UTC 2015
Author: markj
Date: Mon Dec 7 21:49:32 2015
New Revision: 291963
URL: https://svnweb.freebsd.org/changeset/base/291963
Log:
MFV r289003:
6271 dtrace caused excessive fork time
Author: Bryan Cantrill <bryan at joyent.com>
Reviewed by: Adam Leventhal <ahl at delphix.com>
Reviewed by: Dan McDonald <danmcd at omniti.com>
Reviewed by: Richard Lowe <richlowe at richlowe.net>
Approved by: Gordon Ross <gwr at nexenta.com>
illumos/illumos-gate at 7bd3c1d12d0c764e1517c3aca62c634409356764
Added:
head/cddl/contrib/opensolaris/cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh
- copied, changed from r289003, vendor/illumos/dist/cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh
head/cddl/contrib/opensolaris/cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh.out
- copied unchanged from r289003, vendor/illumos/dist/cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh.out
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c
head/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h
Directory Properties:
head/cddl/contrib/opensolaris/ (props changed)
head/sys/cddl/contrib/opensolaris/ (props changed)
Copied and modified: head/cddl/contrib/opensolaris/cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh (from r289003, vendor/illumos/dist/cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh)
==============================================================================
--- vendor/illumos/dist/cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh Thu Oct 8 04:29:39 2015 (r289003, copy source)
+++ head/cddl/contrib/opensolaris/cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh Mon Dec 7 21:49:32 2015 (r291963)
@@ -59,14 +59,14 @@ provider doogle {
};
EOF
- gcc -m32 -c $oogle.c
+ cc -c $oogle.c
if [ $? -ne 0 ]; then
print -u2 "failed to compile $oogle.c"
exit 1
fi
- $dtrace -G -32 -s $oogle.d $oogle.o -o $oogle.d.o
+ $dtrace -G -s $oogle.d $oogle.o -o $oogle.d.o
if [ $? -ne 0 ]; then
print -u2 "failed to process $oogle.d"
@@ -79,7 +79,7 @@ done
echo "}" >> test.c
-gcc -m32 -o test test.c $objs
+cc -o test test.c $objs
if [ $? -ne 0 ]; then
print -u2 "failed to compile test.c"
@@ -95,5 +95,5 @@ if [ $? -ne 0 ]; then
fi
cd /
-/usr/bin/rm -rf $DIR
+rm -rf $DIR
exit 0
Copied: head/cddl/contrib/opensolaris/cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh.out (from r289003, vendor/illumos/dist/cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh.out)
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ head/cddl/contrib/opensolaris/cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh.out Mon Dec 7 21:49:32 2015 (r291963, copy of r289003, vendor/illumos/dist/cmd/dtrace/test/tst/common/usdt/tst.sameprovmulti.ksh.out)
@@ -0,0 +1,4 @@
+bagnoogle 1
+cockoogle 1
+stalloogle 1
+
Modified: head/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c Mon Dec 7 21:44:05 2015 (r291962)
+++ head/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c Mon Dec 7 21:49:32 2015 (r291963)
@@ -15749,8 +15749,8 @@ dtrace_helper_provider_add(dof_helper_t
* Check to make sure this isn't a duplicate.
*/
for (i = 0; i < help->dthps_nprovs; i++) {
- if (dofhp->dofhp_dof ==
- help->dthps_provs[i]->dthp_prov.dofhp_dof)
+ if (dofhp->dofhp_addr ==
+ help->dthps_provs[i]->dthp_prov.dofhp_addr)
return (EALREADY);
}
@@ -16110,7 +16110,14 @@ dtrace_helper_slurp(dof_hdr_t *dof, dof_
dtrace_enabling_destroy(enab);
if (dhp != NULL && nprovs > 0) {
+ /*
+ * Now that this is in-kernel, we change the sense of the
+ * members: dofhp_dof denotes the in-kernel copy of the DOF
+ * and dofhp_addr denotes the address at user-level.
+ */
+ dhp->dofhp_addr = dhp->dofhp_dof;
dhp->dofhp_dof = (uint64_t)(uintptr_t)dof;
+
if (dtrace_helper_provider_add(dhp, help, gen) == 0) {
mutex_exit(&dtrace_lock);
dtrace_helper_provider_register(p, help, dhp);
Modified: head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c Mon Dec 7 21:44:05 2015 (r291962)
+++ head/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c Mon Dec 7 21:49:32 2015 (r291963)
@@ -2117,6 +2117,18 @@ fasttrap_meta_provide(void *arg, dtrace_
return (provider);
}
+/*
+ * We know a few things about our context here: we know that the probe being
+ * created doesn't already exist (DTrace won't load DOF at the same address
+ * twice, even if explicitly told to do so) and we know that we are
+ * single-threaded with respect to the meta provider machinery. Knowing that
+ * this is a new probe and that there is no way for us to race with another
+ * operation on this provider allows us an important optimization: we need not
+ * lookup a probe before adding it. Saving this lookup is important because
+ * this code is in the fork path for processes with USDT probes, and lookups
+ * here are potentially very expensive because of long hash conflicts on
+ * module, function and name (DTrace doesn't hash on provider name).
+ */
/*ARGSUSED*/
static void
fasttrap_meta_create_probe(void *arg, void *parg,
@@ -2153,19 +2165,6 @@ fasttrap_meta_create_probe(void *arg, vo
return;
}
- /*
- * Grab the creation lock to ensure consistency between calls to
- * dtrace_probe_lookup() and dtrace_probe_create() in the face of
- * other threads creating probes.
- */
- mutex_enter(&provider->ftp_cmtx);
-
- if (dtrace_probe_lookup(provider->ftp_provid, dhpb->dthpb_mod,
- dhpb->dthpb_func, dhpb->dthpb_name) != 0) {
- mutex_exit(&provider->ftp_cmtx);
- return;
- }
-
ntps = dhpb->dthpb_noffs + dhpb->dthpb_nenoffs;
ASSERT(ntps > 0);
@@ -2173,7 +2172,6 @@ fasttrap_meta_create_probe(void *arg, vo
if (fasttrap_total > fasttrap_max) {
atomic_add_32(&fasttrap_total, -ntps);
- mutex_exit(&provider->ftp_cmtx);
return;
}
@@ -2237,8 +2235,6 @@ fasttrap_meta_create_probe(void *arg, vo
*/
pp->ftp_id = dtrace_probe_create(provider->ftp_provid, dhpb->dthpb_mod,
dhpb->dthpb_func, dhpb->dthpb_name, FASTTRAP_OFFSET_AFRAMES, pp);
-
- mutex_exit(&provider->ftp_cmtx);
}
/*ARGSUSED*/
Modified: head/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h Mon Dec 7 21:44:05 2015 (r291962)
+++ head/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h Mon Dec 7 21:49:32 2015 (r291963)
@@ -2205,12 +2205,18 @@ extern void dtrace_probe(dtrace_id_t, ui
*
* 1.2.4 Caller's context
*
- * dtms_create_probe() is called from either ioctl() or module load context.
- * The DTrace framework is locked in such a way that meta providers may not
- * register or unregister. This means that the meta provider cannot call
- * dtrace_meta_register() or dtrace_meta_unregister(). However, the context is
- * such that the provider may (and is expected to) call provider-related
- * DTrace provider APIs including dtrace_probe_create().
+ * dtms_create_probe() is called from either ioctl() or module load context
+ * in the context of a newly-created provider (that is, a provider that
+ * is a result of a call to dtms_provide_pid()). The DTrace framework is
+ * locked in such a way that meta providers may not register or unregister,
+ * such that no other thread can call into a meta provider operation and that
+ * atomicity is assured with respect to meta provider operations across
+ * dtms_provide_pid() and subsequent calls to dtms_create_probe().
+ * The context is thus effectively single-threaded with respect to the meta
+ * provider, and that the meta provider cannot call dtrace_meta_register()
+ * or dtrace_meta_unregister(). However, the context is such that the
+ * provider may (and is expected to) call provider-related DTrace provider
+ * APIs including dtrace_probe_create().
*
* 1.3 void *dtms_provide_pid(void *arg, dtrace_meta_provider_t *mprov,
* pid_t pid)
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