From: Peter Zijlstra <peterz@infradead.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ingo Molnar <mingo@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Tejun Heo <tj@kernel.org>, Suren Baghdasaryan <surenb@google.com>,
Daniel Drake <drake@endlessm.com>,
Vinayak Menon <vinmenon@codeaurora.org>,
Christopher Lameter <cl@linux.com>,
Peter Enderborg <peter.enderborg@sony.com>,
Shakeel Butt <shakeelb@google.com>,
Mike Galbraith <efault@gmx.de>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH 8/9] psi: pressure stall information for CPU, memory, and IO
Date: Fri, 7 Sep 2018 12:21:46 +0200 [thread overview]
Message-ID: <20180907102146.GI24142@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20180907101634.GO24106@hirez.programming.kicks-ass.net>
On Fri, Sep 07, 2018 at 12:16:34PM +0200, Peter Zijlstra wrote:
> This does the whole seqcount thing 6x, which is a bit of a waste.
>
> struct snapshot {
> u32 times[NR_PSI_STATES];
> };
>
> static inline struct snapshot get_times_snapshot(struct psi_group *pg, int cpu)
> {
> struct pci_group_cpu *pgc = per_cpu_ptr(pg->pcpu, cpu);
> struct snapshot s;
> unsigned int seq;
> u32 delta;
> int i;
>
> do {
> seq = read_seqcount_begin(&pgc->seq);
>
> delta = cpu_clock(cpu) - pgc->state_start;
> for (i = 0; i < NR_PSI_STATES; i++) {
> s.times[i] = gpc->times[i];
> if (test_state(pgc->tasks, i))
> s.times[i] += delta;
> }
>
> } while (read_seqcount_retry(&pgc->seq, seq);
Sorry, I forgot the whole times_prev thing:
for (i = 0; i < NR_PSI_STATES; i++) {
tmp = s.times[i];
s.times[i] -= pgc->times_prev[i];
pgc->times_prev[i] = tmp;
}
> return s;
> }
>
>
> for_each_possible_cpu(cpu) {
> struct snapshot s = get_times_snapshot(pg, cpu);
>
> nonidle = nsecs_to_jiffies(s.times[PSI_NONIDLE]);
> nonidle_total += nonidle;
>
> for (i = 0; i < PSI_NONIDLE; i++)
> deltas[s] += (u64)s.times[i] * nonidle;
>
> /* ... */
>
> }
>
>
> It's a bit cumbersome, but that's because of C.
next prev parent reply other threads:[~2018-09-07 10:22 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-28 17:22 [PATCH 0/9] psi: pressure stall information for CPU, memory, and IO v4 Johannes Weiner
2018-08-28 17:22 ` [PATCH 1/9] mm: workingset: don't drop refault information prematurely Johannes Weiner
2018-08-28 17:22 ` [PATCH 2/9] mm: workingset: tell cache transitions from workingset thrashing Johannes Weiner
2018-08-28 17:22 ` [PATCH 3/9] delayacct: track delays from thrashing cache pages Johannes Weiner
2018-08-28 17:22 ` [PATCH 4/9] sched: loadavg: consolidate LOAD_INT, LOAD_FRAC, CALC_LOAD Johannes Weiner
2018-09-12 23:28 ` Andrew Morton
2018-09-13 1:49 ` Johannes Weiner
2018-08-28 17:22 ` [PATCH 5/9] sched: loadavg: make calc_load_n() public Johannes Weiner
2018-08-28 17:22 ` [PATCH 6/9] sched: sched.h: make rq locking and clock functions available in stats.h Johannes Weiner
2018-08-28 17:22 ` [PATCH 7/9] sched: introduce this_rq_lock_irq() Johannes Weiner
2018-08-28 17:22 ` [PATCH 8/9] psi: pressure stall information for CPU, memory, and IO Johannes Weiner
2018-08-28 20:11 ` Randy Dunlap
2018-08-28 20:56 ` Johannes Weiner
2018-08-28 21:30 ` Randy Dunlap
2018-09-07 10:16 ` Peter Zijlstra
2018-09-07 10:21 ` Peter Zijlstra [this message]
2018-09-07 14:44 ` Johannes Weiner
2018-09-07 14:58 ` Peter Zijlstra
2018-09-07 17:50 ` Johannes Weiner
2018-09-07 10:24 ` Peter Zijlstra
2018-09-07 14:54 ` Johannes Weiner
2018-08-28 17:22 ` [PATCH 9/9] psi: cgroup support Johannes Weiner
2018-09-05 21:43 ` [PATCH 0/9] psi: pressure stall information for CPU, memory, and IO v4 Johannes Weiner
2018-09-07 7:36 ` Daniel Drake
2018-09-07 7:46 ` Peter Zijlstra
2018-09-07 11:04 ` Peter Zijlstra
2018-09-07 15:09 ` Johannes Weiner
2018-09-07 15:58 ` Suren Baghdasaryan
2018-09-17 5:22 ` Daniel Drake
2018-09-18 15:53 ` Suren Baghdasaryan
2018-09-25 22:05 ` Suren Baghdasaryan
2018-09-17 13:29 ` peter enderborg
2018-09-17 13:40 ` Peter Zijlstra
2018-09-18 16:03 ` Suren Baghdasaryan
2018-10-19 2:07 ` Andrew Morton
2018-10-23 17:29 ` Johannes Weiner
2018-10-23 17:41 ` Peter Zijlstra
[not found] <20180801151958.32590-1-hannes@cmpxchg.org>
2018-08-01 15:19 ` [PATCH 8/9] psi: pressure stall information for CPU, memory, and IO Johannes Weiner
2018-08-03 16:56 ` Peter Zijlstra
2018-08-06 15:05 ` Johannes Weiner
2018-08-06 15:25 ` Peter Zijlstra
2018-08-06 15:40 ` Johannes Weiner
2018-08-06 15:19 ` Johannes Weiner
2018-08-06 16:03 ` Peter Zijlstra
2018-08-21 19:44 ` Johannes Weiner
2018-08-22 9:16 ` Peter Zijlstra
2018-08-03 17:07 ` Peter Zijlstra
2018-08-06 15:23 ` Johannes Weiner
2018-08-03 17:15 ` Peter Zijlstra
2018-08-03 17:21 ` Peter Zijlstra
2018-08-21 20:11 ` Johannes Weiner
2018-08-22 9:10 ` Peter Zijlstra
2018-08-22 17:28 ` Johannes Weiner
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