Date: Sat, 16 Jul 2011 09:34:45 +0000 From: Alexander Best <arundel@freebsd.org> To: John Baldwin <jhb@freebsd.org> Cc: current@freebsd.org Subject: Re: [PATCH] Export per-thread resource usage via sysctl Message-ID: <20110716093445.GA15357@freebsd.org> In-Reply-To: <201107151343.40065.jhb@freebsd.org> References: <201107151343.40065.jhb@freebsd.org>
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On Fri Jul 15 11, John Baldwin wrote:
> This change exports each individual thread's resource usage via sysctl when
> individual threads are requested via KERN_PROC_INC_THREAD. This generally
> works correctly with 'top -m io' after the previous change to revert top(1)
> back to using KERN_PROC_PROC when threads are not enabled. There is one issue
> in that top doesn't necessarily DTRT when disabling/enabling threads via 'H'
> at runtime while in io mode. I may do some further work to clean that up.
> However, for just top run it will now show per-thread stats instead of
> duplicating the per-process stats for each thread.
i'm not sure, if i understand what the patch is supposed to do. however after
applying it, and recompiling/reinstalling the kernel, 'top -mio' displays the
same stats for each thread of a process. if i understood you correctly, each
thread should have individual stats.
i'm running r224068 on amd64 and just reinstalled 'top'. anything i am missing?
cheers.
alex
>
> It also fixes a bug in that the code in calcru() to try to account for the
> current thread's runtime wasn't correctly accounting charging that time to
> the current thread.
>
> Index: sys/kern/kern_proc.c
> ===================================================================
> --- sys/kern/kern_proc.c (revision 224058)
> +++ sys/kern/kern_proc.c (working copy)
> @@ -848,6 +848,8 @@
> kp->ki_tdaddr = td;
> PROC_LOCK_ASSERT(p, MA_OWNED);
>
> + if (preferthread)
> + PROC_SLOCK(p);
> thread_lock(td);
> if (td->td_wmesg != NULL)
> strlcpy(kp->ki_wmesg, td->td_wmesg, sizeof(kp->ki_wmesg));
> @@ -899,6 +901,7 @@
> kp->ki_pri.pri_user = td->td_user_pri;
>
> if (preferthread) {
> + rufetchtd(td, &kp->ki_rusage);
> kp->ki_runtime = cputick2usec(td->td_rux.rux_runtime);
> kp->ki_pctcpu = sched_pctcpu(td);
> kp->ki_estcpu = td->td_estcpu;
> @@ -911,6 +914,8 @@
> kp->ki_siglist = td->td_siglist;
> kp->ki_sigmask = td->td_sigmask;
> thread_unlock(td);
> + if (preferthread)
> + PROC_SUNLOCK(p);
> }
>
> /*
> Index: sys/kern/kern_resource.c
> ===================================================================
> --- sys/kern/kern_resource.c (revision 224058)
> +++ sys/kern/kern_resource.c (working copy)
> @@ -813,7 +813,7 @@
> calcru(struct proc *p, struct timeval *up, struct timeval *sp)
> {
> struct thread *td;
> - uint64_t u;
> + uint64_t runtime, u;
>
> PROC_LOCK_ASSERT(p, MA_OWNED);
> PROC_SLOCK_ASSERT(p, MA_OWNED);
> @@ -826,7 +826,9 @@
> td = curthread;
> if (td->td_proc == p) {
> u = cpu_ticks();
> - p->p_rux.rux_runtime += u - PCPU_GET(switchtime);
> + runtime = u - PCPU_GET(switchtime);
> + td->td_runtime += runtime;
> + td->td_incruntime += runtime;
> PCPU_SET(switchtime, u);
> }
> /* Make sure the per-thread stats are current. */
> @@ -838,6 +840,34 @@
> calcru1(p, &p->p_rux, up, sp);
> }
>
> +/* Collect resource usage for a single thread. */
> +void
> +rufetchtd(struct thread *td, struct rusage *ru)
> +{
> + struct proc *p;
> + uint64_t runtime, u;
> +
> + p = td->td_proc;
> + PROC_SLOCK_ASSERT(p, MA_OWNED);
> + THREAD_LOCK_ASSERT(td, MA_OWNED);
> + /*
> + * If we are getting stats for the current thread, then add in the
> + * stats that this thread has accumulated in its current time slice.
> + * We reset the thread and CPU state as if we had performed a context
> + * switch right here.
> + */
> + if (td == curthread) {
> + u = cpu_ticks();
> + runtime = u - PCPU_GET(switchtime);
> + td->td_runtime += runtime;
> + td->td_incruntime += runtime;
> + PCPU_SET(switchtime, u);
> + }
> + ruxagg(p, td);
> + *ru = td->td_ru;
> + calcru1(p, &td->td_rux, &ru->ru_utime, &ru->ru_stime);
> +}
> +
> static void
> calcru1(struct proc *p, struct rusage_ext *ruxp, struct timeval *up,
> struct timeval *sp)
> @@ -955,12 +985,10 @@
>
> case RUSAGE_THREAD:
> PROC_SLOCK(p);
> - ruxagg(p, td);
> - PROC_SUNLOCK(p);
> thread_lock(td);
> - *rup = td->td_ru;
> - calcru1(p, &td->td_rux, &rup->ru_utime, &rup->ru_stime);
> + rufetchtd(td, rup);
> thread_unlock(td);
> + PROC_SUNLOCK(p);
> break;
>
> default:
> Index: sys/sys/resourcevar.h
> ===================================================================
> --- sys/sys/resourcevar.h (revision 224058)
> +++ sys/sys/resourcevar.h (working copy)
> @@ -136,6 +136,7 @@
> void rufetch(struct proc *p, struct rusage *ru);
> void rufetchcalc(struct proc *p, struct rusage *ru, struct timeval *up,
> struct timeval *sp);
> +void rufetchtd(struct thread *td, struct rusage *ru);
> void ruxagg(struct proc *p, struct thread *td);
> int suswintr(void *base, int word);
> struct uidinfo
>
> --
> John Baldwin
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