5b1a8eb397
Keep track of time spent by the cpu in various contexts in units of "cputicks" and scale to real-world microsec^H^H^H^H^H^H^H^Hclock_t only when somebody wants to inspect the numbers. For now "cputicks" are still derived from the current timecounter and therefore things should by definition remain sensible also on SMP machines. (The main reason for this first milestone commit is to verify that hypothesis.) On slower machines, the avoided multiplications to normalize timestams at every context switch, comes out as a 5-7% better score on the unixbench/context1 microbenchmark. On more modern hardware no change in performance is seen.
282 lines
7.6 KiB
C
282 lines
7.6 KiB
C
/*-
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* Copyright (C) 1994, David Greenman
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* the University of Utah, and William Jolitz.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)trap.c 7.4 (Berkeley) 5/13/91
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_ktrace.h"
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#include "opt_mac.h"
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#ifdef __i386__
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#include "opt_npx.h"
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#endif
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#include <sys/param.h>
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mac.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/ktr.h>
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#include <sys/resourcevar.h>
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#include <sys/sched.h>
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#include <sys/signalvar.h>
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#include <sys/systm.h>
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#include <sys/vmmeter.h>
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#ifdef KTRACE
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#include <sys/uio.h>
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#include <sys/ktrace.h>
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#endif
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#include <machine/cpu.h>
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#include <machine/pcb.h>
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/*
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* Define the code needed before returning to user mode, for
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* trap and syscall.
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*
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* MPSAFE
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*/
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void
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userret(td, frame, oticks)
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struct thread *td;
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struct trapframe *frame;
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u_int oticks;
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{
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struct proc *p = td->td_proc;
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CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid,
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p->p_comm);
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#ifdef DIAGNOSTIC
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/* Check that we called signotify() enough. */
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PROC_LOCK(p);
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mtx_lock_spin(&sched_lock);
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if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 ||
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(td->td_flags & TDF_ASTPENDING) == 0))
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printf("failed to set signal flags properly for ast()\n");
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mtx_unlock_spin(&sched_lock);
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PROC_UNLOCK(p);
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#endif
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#ifdef KTRACE
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KTRUSERRET(td);
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#endif
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/*
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* If this thread tickled GEOM, we need to wait for the giggling to
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* stop before we return to userland
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*/
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if (td->td_pflags & TDP_GEOM)
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g_waitidle();
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/*
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* We need to check to see if we have to exit or wait due to a
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* single threading requirement or some other STOP condition.
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* Don't bother doing all the work if the stop bits are not set
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* at this time.. If we miss it, we miss it.. no big deal.
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*/
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if (P_SHOULDSTOP(p)) {
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PROC_LOCK(p);
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thread_suspend_check(0); /* Can suspend or kill */
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PROC_UNLOCK(p);
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}
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/*
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* Do special thread processing, e.g. upcall tweaking and such.
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*/
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if (p->p_flag & P_SA)
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thread_userret(td, frame);
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/*
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* Charge system time if profiling.
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*/
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if (p->p_flag & P_PROFIL) {
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quad_t ticks;
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ticks = td->td_sticks - oticks;
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addupc_task(td, TRAPF_PC(frame), (u_int)ticks * psratio);
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}
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/*
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* Let the scheduler adjust our priority etc.
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*/
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sched_userret(td);
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KASSERT(td->td_locks == 0,
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("userret: Returning with %d locks held.", td->td_locks));
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}
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/*
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* Process an asynchronous software trap.
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* This is relatively easy.
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* This function will return with preemption disabled.
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*/
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void
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ast(struct trapframe *framep)
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{
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struct thread *td;
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struct proc *p;
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struct ksegrp *kg;
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struct rlimit rlim;
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u_int sticks;
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int sflag;
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int flags;
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int sig;
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#if defined(DEV_NPX) && !defined(SMP)
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int ucode;
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ksiginfo_t ksi;
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#endif
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td = curthread;
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p = td->td_proc;
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kg = td->td_ksegrp;
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CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid,
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p->p_comm);
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KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode"));
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WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode");
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mtx_assert(&Giant, MA_NOTOWNED);
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mtx_assert(&sched_lock, MA_NOTOWNED);
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td->td_frame = framep;
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sticks = td->td_sticks;
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if ((p->p_flag & P_SA) && (td->td_mailbox == NULL))
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thread_user_enter(td);
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/*
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* This updates the p_sflag's for the checks below in one
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* "atomic" operation with turning off the astpending flag.
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* If another AST is triggered while we are handling the
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* AST's saved in sflag, the astpending flag will be set and
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* ast() will be called again.
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*/
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mtx_lock_spin(&sched_lock);
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flags = td->td_flags;
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sflag = p->p_sflag;
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p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU);
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#ifdef MAC
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p->p_sflag &= ~PS_MACPEND;
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#endif
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td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK |
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TDF_NEEDRESCHED | TDF_INTERRUPT);
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cnt.v_soft++;
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mtx_unlock_spin(&sched_lock);
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/*
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* XXXKSE While the fact that we owe a user profiling
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* tick is stored per KSE in this code, the statistics
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* themselves are still stored per process.
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* This should probably change, by which I mean that
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* possibly the location of both might change.
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*/
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if (td->td_ucred != p->p_ucred)
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cred_update_thread(td);
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if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) {
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addupc_task(td, td->td_profil_addr, td->td_profil_ticks);
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td->td_profil_ticks = 0;
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td->td_pflags &= ~TDP_OWEUPC;
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}
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if (sflag & PS_ALRMPEND) {
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PROC_LOCK(p);
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psignal(p, SIGVTALRM);
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PROC_UNLOCK(p);
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}
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#if defined(DEV_NPX) && !defined(SMP)
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if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) {
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atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags,
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PCB_NPXTRAP);
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ucode = npxtrap();
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if (ucode != -1) {
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ksiginfo_init_trap(&ksi);
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ksi.ksi_signo = SIGFPE;
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ksi.ksi_code = ucode;
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trapsignal(td, &ksi);
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}
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}
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#endif
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if (sflag & PS_PROFPEND) {
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PROC_LOCK(p);
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psignal(p, SIGPROF);
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PROC_UNLOCK(p);
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}
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if (sflag & PS_XCPU) {
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PROC_LOCK(p);
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lim_rlimit(p, RLIMIT_CPU, &rlim);
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mtx_lock_spin(&sched_lock);
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if (p->p_rux.rux_runtime >= rlim.rlim_max * cpu_tickrate()) {
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mtx_unlock_spin(&sched_lock);
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killproc(p, "exceeded maximum CPU limit");
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} else {
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if (p->p_cpulimit < rlim.rlim_max)
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p->p_cpulimit += 5;
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mtx_unlock_spin(&sched_lock);
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psignal(p, SIGXCPU);
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}
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PROC_UNLOCK(p);
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}
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#ifdef MAC
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if (sflag & PS_MACPEND)
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mac_thread_userret(td);
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#endif
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if (flags & TDF_NEEDRESCHED) {
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_CSW))
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ktrcsw(1, 1);
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#endif
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mtx_lock_spin(&sched_lock);
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sched_prio(td, kg->kg_user_pri);
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mi_switch(SW_INVOL, NULL);
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mtx_unlock_spin(&sched_lock);
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_CSW))
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ktrcsw(0, 1);
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#endif
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}
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if (flags & TDF_NEEDSIGCHK) {
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PROC_LOCK(p);
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mtx_lock(&p->p_sigacts->ps_mtx);
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while ((sig = cursig(td)) != 0)
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postsig(sig);
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mtx_unlock(&p->p_sigacts->ps_mtx);
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PROC_UNLOCK(p);
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}
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userret(td, framep, sticks);
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mtx_assert(&Giant, MA_NOTOWNED);
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}
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