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Subject[RFC PATCH -tip 2/2 v2] add a scripts for pagecache usage per process
The scripts are implemented based on the trace stream scripting support.
And the scripts implement the following.
- how many pagecaches each process has per each file
- how many pages are cached per each file
- how many pagecaches each process shares

To monitor pagecache usage per a process, run "pagecache-usage-record" to
record perf data for "pagecache-usage.pl" and run "pagecache-usage-report"
to display.

The below outputs show execution sample.

[file list]
device inode caches
--------------------------------
253:0 1051413 130
253:0 1051399 2
253:0 1051414 44
253:0 1051417 154
[process list]
o postmaster-2330
cached added removed indirect
device inode pages pages pages removed pages
----------------------------------------------------------------
253:0 1051399 0 2 0 0
253:0 1051417 154 0 0 0
253:0 1051413 130 0 0 0
253:0 1051414 44 0 0 0
----------------------------------------------------------------
total: 337 2 0 0
>From the output, we can know some information like:

- if "added pages" > "cached pages" on process list then
It means repeating add/remove pagecache many times.
=> Bad case for pagecache usage
- if "added pages" <= "cached pages" on process list then
It means no unnecessary I/O operations.
=> Good case for pagecache usage.

- if "caches" on file list >
sum "cached pages" per each file on process list then
It means there are unneccessary pagecaches in the memory.
=> Bad case for pagecache usage
Signed-off-by: Keiichi Kii <k-keiichi@bx.jp.nec.com>
Cc: Atsushi Tsuji <a-tsuji@bk.jp.nec.com>
---
tools/perf/scripts/perl/bin/pagecache-usage-record | 7
tools/perf/scripts/perl/bin/pagecache-usage-report | 6
tools/perf/scripts/perl/pagecache-usage.pl | 160 +++++++++++++++++++++
3 files changed, 173 insertions(+)
Index: linux-2.6-tip/tools/perf/scripts/perl/bin/pagecache-usage-record
===================================================================
--- /dev/null
+++ linux-2.6-tip/tools/perf/scripts/perl/bin/pagecache-usage-record
@@ -0,0 +1,7 @@
+#!/bin/bash
+perf record -c 1 -f -a -M -R -e filemap:add_to_page_cache -e filemap:find_get_page -e filemap:remove_from_page_cache
+
+
+
+
+
Index: linux-2.6-tip/tools/perf/scripts/perl/bin/pagecache-usage-report
===================================================================
--- /dev/null
+++ linux-2.6-tip/tools/perf/scripts/perl/bin/pagecache-usage-report
@@ -0,0 +1,6 @@
+#!/bin/bash
+# description: pagecache usage per process
+perf trace -s ~/libexec/perf-core/scripts/perl/pagecache-usage.pl
+
+
+
Index: linux-2.6-tip/tools/perf/scripts/perl/pagecache-usage.pl
===================================================================
--- /dev/null
+++ linux-2.6-tip/tools/perf/scripts/perl/pagecache-usage.pl
@@ -0,0 +1,160 @@
+# perf trace event handlers, generated by perf trace -g perl
+# Licensed under the terms of the GNU GPL License version 2
+
+# The common_* event handler fields are the most useful fields common to
+# all events. They don't necessarily correspond to the 'common_*' fields
+# in the format files. Those fields not available as handler params can
+# be retrieved using Perl functions of the form common_*($context).
+# See Context.pm for the list of available functions.
+
+use lib "$ENV{'PERF_EXEC_PATH'}/scripts/perl/Perf-Trace-Util/lib";
+use lib "./Perf-Trace-Util/lib";
+use Perf::Trace::Core;
+use Perf::Trace::Context;
+use Perf::Trace::Util;
+use List::Util qw/sum/;
+my %files;
+my %processes;
+my %records;
+
+sub trace_end
+{
+ print_pagecache_usage_per_file();
+ print "\n";
+ print_pagecache_usage_per_process();
+ print_unhandled();
+}
+
+sub filemap::remove_from_page_cache
+{
+ my ($event_name, $context, $common_cpu, $common_secs, $common_nsecs,
+ $common_pid, $common_comm,
+ $s_dev, $i_ino, $offset) = @_;
+ my $f = \%{$files{$s_dev}{$i_ino}};
+ my $r = \%{$records{$common_comm."-".$common_pid}{$f}};
+
+ delete $$f{$offset};
+ $$r{inode} = $i_ino;
+ $$r{dev} = $s_dev;
+ if (exists $$r{added}{$offset}) {
+ $$r{removed}++;
+ } else {
+ $$r{indirect_removed}++;
+ }
+}
+
+sub filemap::add_to_page_cache
+{
+ my ($event_name, $context, $common_cpu, $common_secs, $common_nsecs,
+ $common_pid, $common_comm,
+ $s_dev, $i_ino, $offset) = @_;
+ my $f = \%{$files{$s_dev}{$i_ino}};
+ my $r = \%{$records{$common_comm."-".$common_pid}{$f}};
+
+ $$f{$offset}++;
+ $$r{added}{$offset}++;
+ $$r{inode} = $i_ino;
+ $$r{dev} = $s_dev;
+}
+
+sub filemap::find_get_page
+{
+ my ($event_name, $context, $common_cpu, $common_secs, $common_nsecs,
+ $common_pid, $common_comm,
+ $s_dev, $i_ino, $offset, $page) = @_;
+ my $f = \%{$files{$s_dev}{$i_ino}};
+ my $r = \%{$records{$common_comm."-".$common_pid}{$f}};
+
+ if ($page != 0) {
+ $$f{$offset}++;
+ $$r{cached}++;
+ $$r{inode} = $i_ino;
+ $$r{dev} = $s_dev;
+ }
+}
+
+my %unhandled;
+
+sub trace_unhandled
+{
+ my ($event_name, $context, $common_cpu, $common_secs, $common_nsecs,
+ $common_pid, $common_comm) = @_;
+
+ $unhandled{$event_name}++;
+}
+
+sub print_unhandled
+{
+ if ((scalar keys %unhandled) == 0) {
+ print "unhandled events nothing\n";
+ return;
+ }
+
+ print "\nunhandled events:\n\n";
+
+ printf("%-40s %10s\n", "event", "count");
+ printf("%-40s %10s\n", "----------------------------------------",
+ "-----------");
+
+ foreach my $event_name (keys %unhandled) {
+ printf("%-40s %10d\n", $event_name, $unhandled{$event_name});
+ }
+}
+
+sub minor
+{
+ my $dev = shift;
+ return $dev & ((1 << 20) - 1);
+}
+
+sub major
+{
+ my $dev = shift;
+ return $dev >> 20;
+}
+
+sub print_pagecache_usage_per_file
+{
+ print "[file list]\n";
+ printf(" %12s %10s %8s\n", "", "", "cached");
+ printf(" %12s %10s %8s\n", "device", "inode", "pages");
+ printf(" %s\n", '-' x 32);
+ while(my($dev, $file) = each(%files)) {
+ while(my($inode, $r) = each(%$file)) {
+ my $count = values %$r;
+ next if $count == 0;
+ printf(" %12s %10d %8d\n",
+ major($dev).":".minor($dev), $inode, $count);
+ }
+ }
+}
+
+sub print_pagecache_usage_per_process
+{
+ print "[process list]\n";
+ while(my ($pid, $v) = each(%records)) {
+ my ($sum_cached, $sum_added, $sum_removed, $sum_indirect_removed);
+
+ print "o $pid\n";
+ printf(" %12s %10s %8s %8s %8s %13s\n", "", "",
+ "cached", "added", "removed", "indirect");
+ printf(" %12s %10s %8s %8s %8s %13s\n", "device", "inode",
+ "pages", "pages", "pages", "removed pages");
+ printf(" %s\n", '-' x 64);
+ while(my ($file, $r) = each(%$v)) {
+ my $added_num = List::Util::sum(values %{$$r{added}});
+ $sum_cached += $$r{cached};
+ $sum_added += $added_num;
+ $sum_removed += $$r{removed};
+ $sum_indirect_removed += $$r{indirect_removed};
+ printf(" %12s %10d %8d %8d %8d %13d\n",
+ major($$r{dev}).":".minor($$r{dev}), $$r{inode},
+ $$r{cached}, $added_num, $$r{removed},
+ $$r{indirect_removed});
+ }
+ printf(" %s\n", '-' x 64);
+ printf(" total: %5s %10s %8d %8d %8d %13d\n", "", "", $sum_cached,
+ $sum_added, $sum_removed, $sum_indirect_removed);
+ print "\n";
+ }
+}




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