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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A71C6C07E95 for ; Wed, 7 Jul 2021 21:39:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F40B61CC0 for ; Wed, 7 Jul 2021 21:39:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233066AbhGGVmL (ORCPT ); Wed, 7 Jul 2021 17:42:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:45756 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233018AbhGGVmE (ORCPT ); Wed, 7 Jul 2021 17:42:04 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 3974F61CB2; Wed, 7 Jul 2021 21:39:23 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.94.2) (envelope-from ) id 1m1FGM-00173V-4R; Wed, 07 Jul 2021 17:39:22 -0400 Message-ID: <20210707213921.980359719@goodmis.org> User-Agent: quilt/0.66 Date: Wed, 07 Jul 2021 17:36:24 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Tom Zanussi , Masami Hiramatsu , Namhyung Kim , Daniel Bristot de Oliveira Subject: [PATCH 1/2 v3] tracing: Add linear buckets to histogram logic References: <20210707213623.250212325@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (VMware)" There's been several times I wished the histogram logic had a "grouping" feature for the buckets. Currently, each bucket has a size of one. That is, if you trace the amount of requested allocations, each allocation is its own bucket, even if you are interested in what allocates 100 bytes or less, 100 to 200, 200 to 300, etc. Also, without grouping, it fills up the allocated histogram buckets quickly. If you are tracking latency, and don't care if something is 200 microseconds off, or 201 microseconds off, but want to track them by say 10 microseconds each. This can not currently be done. There is a log2 but that grouping get's too big too fast for a lot of cases. Introduce a "buckets=SIZE" command to each field where it will record in a rounded number. For example: ># echo 'hist:keys=bytes_req.buckets=100:sort=bytes_req' > events/kmem/kmalloc/trigger ># cat events/kmem/kmalloc/hist # event histogram # # trigger info: hist:keys=bytes_req.buckets=100:vals=hitcount:sort=bytes_req.buckets=100:size=2048 [active] # { bytes_req: ~ 0-99 } hitcount: 3149 { bytes_req: ~ 100-199 } hitcount: 1468 { bytes_req: ~ 200-299 } hitcount: 39 { bytes_req: ~ 300-399 } hitcount: 306 { bytes_req: ~ 400-499 } hitcount: 364 { bytes_req: ~ 500-599 } hitcount: 32 { bytes_req: ~ 600-699 } hitcount: 69 { bytes_req: ~ 700-799 } hitcount: 37 { bytes_req: ~ 1200-1299 } hitcount: 16 { bytes_req: ~ 1400-1499 } hitcount: 30 { bytes_req: ~ 2000-2099 } hitcount: 6 { bytes_req: ~ 4000-4099 } hitcount: 2168 { bytes_req: ~ 5000-5099 } hitcount: 6 Totals: Hits: 7690 Entries: 13 Dropped: 0 Reviewed-by: Tom Zanussi Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events_hist.c | 65 ++++++++++++++++++++++++++++---- 1 file changed, 58 insertions(+), 7 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 0207aeed31e6..1d0592051f2f 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -120,6 +120,7 @@ struct hist_field { unsigned int size; unsigned int offset; unsigned int is_signed; + unsigned long buckets; const char *type; struct hist_field *operands[HIST_FIELD_OPERANDS_MAX]; struct hist_trigger_data *hist_data; @@ -218,6 +219,27 @@ static u64 hist_field_log2(struct hist_field *hist_field, return (u64) ilog2(roundup_pow_of_two(val)); } +static u64 hist_field_bucket(struct hist_field *hist_field, + struct tracing_map_elt *elt, + struct trace_buffer *buffer, + struct ring_buffer_event *rbe, + void *event) +{ + struct hist_field *operand = hist_field->operands[0]; + unsigned long buckets = hist_field->buckets; + + u64 val = operand->fn(operand, elt, buffer, rbe, event); + + if (WARN_ON_ONCE(!buckets)) + return val; + + if (val >= LONG_MAX) + val = div64_ul(val, buckets); + else + val = (u64)((unsigned long)val / buckets); + return val * buckets; +} + static u64 hist_field_plus(struct hist_field *hist_field, struct tracing_map_elt *elt, struct trace_buffer *buffer, @@ -317,6 +339,7 @@ enum hist_field_flags { HIST_FIELD_FL_VAR_REF = 1 << 14, HIST_FIELD_FL_CPU = 1 << 15, HIST_FIELD_FL_ALIAS = 1 << 16, + HIST_FIELD_FL_BUCKET = 1 << 17, }; struct var_defs { @@ -1108,7 +1131,8 @@ static const char *hist_field_name(struct hist_field *field, if (field->field) field_name = field->field->name; else if (field->flags & HIST_FIELD_FL_LOG2 || - field->flags & HIST_FIELD_FL_ALIAS) + field->flags & HIST_FIELD_FL_ALIAS || + field->flags & HIST_FIELD_FL_BUCKET) field_name = hist_field_name(field->operands[0], ++level); else if (field->flags & HIST_FIELD_FL_CPU) field_name = "cpu"; @@ -1469,6 +1493,8 @@ static const char *get_hist_field_flags(struct hist_field *hist_field) flags_str = "syscall"; else if (hist_field->flags & HIST_FIELD_FL_LOG2) flags_str = "log2"; + else if (hist_field->flags & HIST_FIELD_FL_BUCKET) + flags_str = "buckets"; else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP_USECS) flags_str = "usecs"; @@ -1657,9 +1683,10 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, goto out; } - if (flags & HIST_FIELD_FL_LOG2) { - unsigned long fl = flags & ~HIST_FIELD_FL_LOG2; - hist_field->fn = hist_field_log2; + if (flags & (HIST_FIELD_FL_LOG2 | HIST_FIELD_FL_BUCKET)) { + unsigned long fl = flags & ~(HIST_FIELD_FL_LOG2 | HIST_FIELD_FL_BUCKET); + hist_field->fn = flags & HIST_FIELD_FL_LOG2 ? hist_field_log2 : + hist_field_bucket; hist_field->operands[0] = create_hist_field(hist_data, field, fl, NULL); hist_field->size = hist_field->operands[0]->size; hist_field->type = kstrdup(hist_field->operands[0]->type, GFP_KERNEL); @@ -1950,7 +1977,7 @@ static struct hist_field *parse_var_ref(struct hist_trigger_data *hist_data, static struct ftrace_event_field * parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file, - char *field_str, unsigned long *flags) + char *field_str, unsigned long *flags, unsigned long *buckets) { struct ftrace_event_field *field = NULL; char *field_name, *modifier, *str; @@ -1977,7 +2004,22 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file, *flags |= HIST_FIELD_FL_LOG2; else if (strcmp(modifier, "usecs") == 0) *flags |= HIST_FIELD_FL_TIMESTAMP_USECS; - else { + else if (strncmp(modifier, "bucket", 6) == 0) { + int ret; + + modifier += 6; + + if (*modifier == 's') + modifier++; + if (*modifier != '=') + goto error; + modifier++; + ret = kstrtoul(modifier, 0, buckets); + if (ret || !(*buckets)) + goto error; + *flags |= HIST_FIELD_FL_BUCKET; + } else { + error: hist_err(tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(modifier)); field = ERR_PTR(-EINVAL); goto out; @@ -2036,6 +2078,7 @@ static struct hist_field *parse_atom(struct hist_trigger_data *hist_data, char *s, *ref_system = NULL, *ref_event = NULL, *ref_var = str; struct ftrace_event_field *field = NULL; struct hist_field *hist_field = NULL; + unsigned long buckets = 0; int ret = 0; s = strchr(str, '.'); @@ -2073,7 +2116,7 @@ static struct hist_field *parse_atom(struct hist_trigger_data *hist_data, } else str = s; - field = parse_field(hist_data, file, str, flags); + field = parse_field(hist_data, file, str, flags, &buckets); if (IS_ERR(field)) { ret = PTR_ERR(field); goto out; @@ -2084,6 +2127,7 @@ static struct hist_field *parse_atom(struct hist_trigger_data *hist_data, ret = -ENOMEM; goto out; } + hist_field->buckets = buckets; return hist_field; out: @@ -4664,6 +4708,11 @@ static void hist_trigger_print_key(struct seq_file *m, } else if (key_field->flags & HIST_FIELD_FL_LOG2) { seq_printf(m, "%s: ~ 2^%-2llu", field_name, *(u64 *)(key + key_field->offset)); + } else if (key_field->flags & HIST_FIELD_FL_BUCKET) { + unsigned long buckets = key_field->buckets; + uval = *(u64 *)(key + key_field->offset); + seq_printf(m, "%s: ~ %llu-%llu", field_name, + uval, uval + buckets -1); } else if (key_field->flags & HIST_FIELD_FL_STRING) { seq_printf(m, "%s: %-50s", field_name, (char *)(key + key_field->offset)); @@ -5103,6 +5152,8 @@ static void hist_field_print(struct seq_file *m, struct hist_field *hist_field) seq_printf(m, ".%s", flags); } } + if (hist_field->buckets) + seq_printf(m, "=%ld", hist_field->buckets); } static int event_hist_trigger_print(struct seq_file *m, -- 2.30.2