From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 892507C for ; Sat, 29 Jul 2023 19:55:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA441C433C7; Sat, 29 Jul 2023 19:55:48 +0000 (UTC) Date: Sat, 29 Jul 2023 15:55:47 -0400 From: Steven Rostedt To: Valentin Schneider Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org, x86@kernel.org, rcu@vger.kernel.org, linux-kselftest@vger.kernel.org, Masami Hiramatsu , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Paolo Bonzini , Wanpeng Li , Vitaly Kuznetsov , Andy Lutomirski , Peter Zijlstra , Frederic Weisbecker , "Paul E. McKenney" , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Andrew Morton , Uladzislau Rezki , Christoph Hellwig , Lorenzo Stoakes , Josh Poimboeuf , Jason Baron , Kees Cook , Sami Tolvanen , Ard Biesheuvel , Nicholas Piggin , Juerg Haefliger , Nicolas Saenz Julienne , "Kirill A. Shutemov" , Nadav Amit , Dan Carpenter , Chuang Wang , Yang Jihong , Petr Mladek , "Jason A. Donenfeld" , Song Liu , Julian Pidancet , Tom Lendacky , Dionna Glaze , Thomas =?UTF-8?B?V2Vpw59zY2h1aA==?= , Juri Lelli , Daniel Bristot de Oliveira , Marcelo Tosatti , Yair Podemsky Subject: Re: [RFC PATCH v2 06/20] tracing/filters: Optimise scalar vs cpumask filtering when the user mask is a single CPU Message-ID: <20230729155547.35719a1f@rorschach.local.home> In-Reply-To: <20230720163056.2564824-7-vschneid@redhat.com> References: <20230720163056.2564824-1-vschneid@redhat.com> <20230720163056.2564824-7-vschneid@redhat.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 20 Jul 2023 17:30:42 +0100 Valentin Schneider wrote: > Steven noted that when the user-provided cpumask contains a single CPU, > then the filtering function can use a scalar as input instead of a > full-fledged cpumask. > > When the mask contains a single CPU, directly re-use the unsigned field > predicate functions. Transform '&' into '==' beforehand. > > Suggested-by: Steven Rostedt > Signed-off-by: Valentin Schneider > --- > kernel/trace/trace_events_filter.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c > index 2fe65ddeb34ef..54d642fabb7f1 100644 > --- a/kernel/trace/trace_events_filter.c > +++ b/kernel/trace/trace_events_filter.c > @@ -1750,7 +1750,7 @@ static int parse_pred(const char *str, void *data, > * then we can treat it as a scalar input. > */ > single = cpumask_weight(pred->mask) == 1; > - if (single && field->filter_type == FILTER_CPUMASK) { > + if (single && field->filter_type != FILTER_CPU) { > pred->val = cpumask_first(pred->mask); > kfree(pred->mask); > } > @@ -1761,6 +1761,11 @@ static int parse_pred(const char *str, void *data, > FILTER_PRED_FN_CPUMASK; > } else if (field->filter_type == FILTER_CPU) { > pred->fn_num = FILTER_PRED_FN_CPU_CPUMASK; > + } else if (single) { > + pred->op = pred->op == OP_BAND ? OP_EQ : pred->op; Nit, the above can be written as: pred->op = pret->op != OP_BAND ? : OP_EQ; -- Steve > + pred->fn_num = select_comparison_fn(pred->op, field->size, false); > + if (pred->op == OP_NE) > + pred->not = 1; > } else { > switch (field->size) { > case 8: