[Xen-devel] [PATCH 21/27] ts-bench-hostcmp-guest-prep: new script

[Dario Faggioli <dario.faggioli@xxxxxxxxxx>]

From: Dario Faggioli <raistlin@xxxxxxxx>

the goal is to run a benchmark both in a guest and
on baremetal, to investigate the performances loss
due to the virtualization overhead.

In order to help accomplishing this, the new script
introduced by this commit modifies a guest's config
file in order for it to have the same number of
vcpus and (almost) the same amount of memory of the
underlying host. This is done under the assumption
that the benchmark will (or has been already) run
on the host too.

It is possible to make the guest have less vcpus
than the host has pcpus, and less memory than the
host, by defining two specific runvars. In fact, in
case of really "beefy" hosts, one may not want to
run the benchmark in an unrealistically large guest.
Of course, specific measures to also limit the host
resources, when running the benchmark on it, should
be taken, if comparing apples to apples is important.

Signed-off-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
Cc: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
Cc: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
---
 ts-bench-hostcmp-guest-prep |   87 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100755 ts-bench-hostcmp-guest-prep

diff --git a/ts-bench-hostcmp-guest-prep b/ts-bench-hostcmp-guest-prep
new file mode 100755
index 0000000..ffde981
--- /dev/null
+++ b/ts-bench-hostcmp-guest-prep
@@ -0,0 +1,87 @@
+#!/usr/bin/perl -w
+# This is part of "osstest", an automated testing framework for Xen.
+# Copyright (C) 2009-2014 Citrix Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+use strict qw(vars);
+use DBI;
+use Osstest;
+use Osstest::TestSupport;
+
+tsreadconfig();
+
+our ($whhost,$gn) = @ARGV;
+$whhost ||= 'host';
+$gn ||= 'debianhvm';
+
+our ($ho,$gho) = ts_get_host_guest($whhost,$gn);
+our $toolstack= toolstack()->{Command};
+
+# We want the guest to have:
+#  - the same number of vcpus than the host has pcpus
+#  - (almost) the same amount of memory the host has
+#
+# For both vcpus and memory, a maximum can be specified via
+# runvars.
+sub fixup () {
+  our ($hnodes,$hcpus,$hmem);
+  our ($cfgfile,$bcpus,$bmem,$hfreemem);
+
+  $hcpus= get_host_cpus($ho);
+  $hmem= get_host_memory($ho);
+  die unless (defined $hcpus and defined $hmem);
+
+  $hnodes= get_host_numanodes($ho);
+  if (defined $hnodes and $hnodes > 1) {
+    logm("WARNING: the host has $hnodes NUMA nodes. This may spoil results");
+  }
+
+  $bcpus= (!defined($r{'max_bench_cpus'})) ? $hcpus :
+      ($r{'max_bench_cpus'} > $hcpus) ? $hcpus : $r{'max_bench_cpus'};
+  $bmem= (!defined($r{'max_bench_mem'})) ? $hmem :
+      ($r{'max_bench_mem'} > $hmem) ? $hmem : $r{'max_bench_mem'};
+
+  $hfreemem = host_get_free_memory($ho,$toolstack);
+  if ($hfreemem < $bmem) {
+    $bmem= $hfreemem - 1024;
+    logm("WARNING: Not enough free memory. Using $bmem MB");
+  }
+
+  logm("Will run the benchmark with: $bcpus vcpus and $bmem MB RAM");
+
+  $cfgfile= $r{"$gho->{Guest}_cfgpath"};
+  target_editfile_root($ho, $cfgfile, sub {
+      while (<EI>) {
+        s/^vcpus.*/vcpus=$bcpus/;
+        s/^memory.*/memory=$bmem/;
+       print EO or die $!;
+      }
+  });
+}
+
+sub start () {
+  # Start the guest...
+  guest_umount_lv($ho, $gho);
+  my $cmd= toolstack()->{Command}." create ".
+      $r{ $gho->{Guest}.'_'. toolstack()->{CfgPathVar} };
+  target_cmd_root($ho, $cmd, 30);
+  # ...And verify it's up and running
+  guest_checkrunning($ho, $gho) or die "$gho->{Name} not running";
+  guest_await($gho, target_var($gho,'boot_timeout'));
+  guest_check_up($gho);
+}
+
+fixup();
+start();


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