From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DAAF5C04EBF for ; Wed, 5 Dec 2018 23:50:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F3A7520892 for ; Wed, 5 Dec 2018 23:50:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F3A7520892 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729029AbeLEXuG (ORCPT ); Wed, 5 Dec 2018 18:50:06 -0500 Received: from mail.kernel.org ([198.145.29.99]:58424 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728933AbeLEXsc (ORCPT ); Wed, 5 Dec 2018 18:48:32 -0500 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 047DD2133F; Wed, 5 Dec 2018 23:48:32 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.91) (envelope-from ) id 1gUgu7-0000Ey-09; Wed, 05 Dec 2018 18:48:31 -0500 Message-Id: <20181205234830.908802709@goodmis.org> User-Agent: quilt/0.65 Date: Wed, 05 Dec 2018 18:48:06 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Namhyung Kim , Masami Hiramatsu , Tom Zanussi , Ravi Bangoria Subject: [for-next][PATCH 17/30] tracing: Add tracefs file buffer_percentage References: <20181205234749.372720574@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (VMware)" Add a "buffer_percentage" file, that allows users to specify how much of the buffer (percentage of pages) need to be filled before waking up a task blocked on a per cpu trace_pipe_raw file. Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ring_buffer.c | 39 ++++++++++++++++----------- kernel/trace/trace.c | 54 +++++++++++++++++++++++++++++++++++++- kernel/trace/trace.h | 1 + 3 files changed, 77 insertions(+), 17 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 9edb628603ab..5434c16f2192 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -489,6 +489,7 @@ struct ring_buffer_per_cpu { local_t commits; local_t pages_touched; local_t pages_read; + long last_pages_touch; size_t shortest_full; unsigned long read; unsigned long read_bytes; @@ -2632,7 +2633,9 @@ static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer, static __always_inline void rb_wakeups(struct ring_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer) { - bool pagebusy; + size_t nr_pages; + size_t dirty; + size_t full; if (buffer->irq_work.waiters_pending) { buffer->irq_work.waiters_pending = false; @@ -2646,24 +2649,27 @@ rb_wakeups(struct ring_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer) irq_work_queue(&cpu_buffer->irq_work.work); } - pagebusy = cpu_buffer->reader_page == cpu_buffer->commit_page; + if (cpu_buffer->last_pages_touch == local_read(&cpu_buffer->pages_touched)) + return; - if (!pagebusy && cpu_buffer->irq_work.full_waiters_pending) { - size_t nr_pages; - size_t dirty; - size_t full; + if (cpu_buffer->reader_page == cpu_buffer->commit_page) + return; - full = cpu_buffer->shortest_full; - nr_pages = cpu_buffer->nr_pages; - dirty = ring_buffer_nr_dirty_pages(buffer, cpu_buffer->cpu); - if (full && nr_pages && (dirty * 100) <= full * nr_pages) - return; + if (!cpu_buffer->irq_work.full_waiters_pending) + return; - cpu_buffer->irq_work.wakeup_full = true; - cpu_buffer->irq_work.full_waiters_pending = false; - /* irq_work_queue() supplies it's own memory barriers */ - irq_work_queue(&cpu_buffer->irq_work.work); - } + cpu_buffer->last_pages_touch = local_read(&cpu_buffer->pages_touched); + + full = cpu_buffer->shortest_full; + nr_pages = cpu_buffer->nr_pages; + dirty = ring_buffer_nr_dirty_pages(buffer, cpu_buffer->cpu); + if (full && nr_pages && (dirty * 100) <= full * nr_pages) + return; + + cpu_buffer->irq_work.wakeup_full = true; + cpu_buffer->irq_work.full_waiters_pending = false; + /* irq_work_queue() supplies it's own memory barriers */ + irq_work_queue(&cpu_buffer->irq_work.work); } /* @@ -4394,6 +4400,7 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer) local_set(&cpu_buffer->commits, 0); local_set(&cpu_buffer->pages_touched, 0); local_set(&cpu_buffer->pages_read, 0); + cpu_buffer->last_pages_touch = 0; cpu_buffer->shortest_full = 0; cpu_buffer->read = 0; cpu_buffer->read_bytes = 0; diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 48d5eb22ff33..d382fd1aa4a6 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6948,7 +6948,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) goto out; - ret = wait_on_pipe(iter, 1); + ret = wait_on_pipe(iter, iter->tr->buffer_percent); if (ret) goto out; @@ -7662,6 +7662,53 @@ static const struct file_operations rb_simple_fops = { .llseek = default_llseek, }; +static ssize_t +buffer_percent_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + char buf[64]; + int r; + + r = tr->buffer_percent; + r = sprintf(buf, "%d\n", r); + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); +} + +static ssize_t +buffer_percent_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + unsigned long val; + int ret; + + ret = kstrtoul_from_user(ubuf, cnt, 10, &val); + if (ret) + return ret; + + if (val > 100) + return -EINVAL; + + if (!val) + val = 1; + + tr->buffer_percent = val; + + (*ppos)++; + + return cnt; +} + +static const struct file_operations buffer_percent_fops = { + .open = tracing_open_generic_tr, + .read = buffer_percent_read, + .write = buffer_percent_write, + .release = tracing_release_generic_tr, + .llseek = default_llseek, +}; + struct dentry *trace_instance_dir; static void @@ -7970,6 +8017,11 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer) trace_create_file("timestamp_mode", 0444, d_tracer, tr, &trace_time_stamp_mode_fops); + tr->buffer_percent = 1; + + trace_create_file("buffer_percent", 0444, d_tracer, + tr, &buffer_percent_fops); + create_trace_options_dir(tr); #if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index ab16eca76e59..08900828d282 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -247,6 +247,7 @@ struct trace_array { int clock_id; int nr_topts; bool clear_trace; + int buffer_percent; struct tracer *current_trace; unsigned int trace_flags; unsigned char trace_flags_index[TRACE_FLAGS_MAX_SIZE]; -- 2.19.1