Date: Tue, 17 Apr 2012 13:19:15 -0400 From: Ryan Stone <rysto32@gmail.com> To: freebsd-hackers@freebsd.org Subject: [PATCH] Implement DTrace "cpu" variable Message-ID: <CAFMmRNxQ3QKCXrF%2B1HiHBUj8=%2B3fjsXmQwrOavQv54XAqnM7Sw@mail.gmail.com>
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Below I have a patch that implements the "cpu" variable in D, as documented here: https://wikis.oracle.com/display/DTrace/Variables#Variables-DTraceBuiltinVariables. I've implemented it as a new builtin variable that returns curcpu. This is different from how it works in OpenSolaris/Illumos -- in those, it's implemented by groping around in curthread. In FreeBSD there are some places deep in the scheduler where curthread->td_oncpu will be set to -1(in preparation for the thread being descheduled) so I prefer to go with an implementation that works in all cases, even if we diverge from upstream a little bit. If there are no objections I intend to commit this[rstone@rstone-laptop head]svn diff Index: cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c =================================================================== --- cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c (revision 234251) +++ cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c (working copy) @@ -497,6 +497,12 @@ { "zonename", DT_IDENT_SCALAR, 0, DIF_VAR_ZONENAME, DT_ATTR_STABCMN, DT_VERS_1_0, &dt_idops_type, "string" }, #endif + +#if !defined(sun) +{ "cpu", DT_IDENT_SCALAR, 0, DIF_VAR_CPU, + DT_ATTR_STABCMN, DT_VERS_1_6_3, &dt_idops_type, "int" }, +#endif + { NULL, 0, 0, 0, { 0, 0, 0 }, 0, NULL, NULL } }; Index: sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c =================================================================== --- sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c (revision 234251) +++ sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c (working copy) @@ -3143,6 +3143,11 @@ return (curthread->td_errno); #endif } +#if !defined(sun) + case DIF_VAR_CPU: { + return curcpu; + } +#endif default: DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP); return (0); Index: sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h =================================================================== --- sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h (revision 234251) +++ sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h (working copy) @@ -251,6 +251,10 @@ #define DIF_VAR_ERRNO 0x0120 /* thread errno */ #define DIF_VAR_EXECARGS 0x0121 /* process arguments */ +#if !defined(sun) +#define DIF_VAR_CPU 0x0200 +#endif + #define DIF_SUBR_RAND 0 #define DIF_SUBR_MUTEX_OWNED 1 #define DIF_SUBR_MUTEX_OWNER 2 to head in the next few days.
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