Re: [libvirt] [Resending][PATCH v2 2/2] x86: Allow sysinfo to fall back on /proc/cpuinfo if demidecode is absent
On Tue, Mar 13, 2012 at 11:10:16AM +0530, Prerna Saxena wrote:
From: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
Date: Tue, 13 Mar 2012 15:33:43 +0530
Subject: [PATCH 2/2] Sysinfo : Allow x86 to fetch sysinfo from
/proc/cpuinfo in the event 'dmidecode' is absent in the system.
Until now, libvirt on x86 flags an error message if dmidecode is not
found. With this patch, the following is a sample output on x86 when
dmidecode is absent:
virsh # sysinfo
<sysinfo type='smbios'>
<processor>
<entry name='socket_destination'>0</entry>
<entry name='type'>Intel(R) Xeon(R) CPU X5570 @ 2.93GHz</entry>
<entry name='family'>6</entry>
<entry name='manufacturer'>GenuineIntel</entry>
</processor>
<processor>
<entry name='socket_destination'>1</entry>
<entry name='type'>Intel(R) Xeon(R) CPU X5570 @ 2.93GHz</entry>
<entry name='family'>6</entry>
<entry name='manufacturer'>GenuineIntel</entry>
</processor>
... (listing for all online CPUs)
</sysinfo>
Based on suggestion from Eric:
(http://www.redhat.com/archives/libvir-list/2012-February/msg00509.html)
Acked-by: Daniel P Berrange <berrange(a)redhat.com>
Signed-off-by: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
---
src/util/sysinfo.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 93 insertions(+), 4 deletions(-)
diff --git a/src/util/sysinfo.c b/src/util/sysinfo.c
index 78efc32..290b69f 100644
--- a/src/util/sysinfo.c
+++ b/src/util/sysinfo.c
@@ -598,6 +598,98 @@ no_memory:
return -1;
}
+/* If a call to 'dmidecode' fails,
+ * extract basic sysinfo from /proc/cpuinfo */
[...]
virSysinfoDefPtr
virSysinfoRead(void) {
char *path;
@@ -607,10 +699,7 @@ virSysinfoRead(void) {
path = virFindFileInPath(SYSINFO_SMBIOS_DECODER);
if (path == NULL) {
- virSmbiosReportError(VIR_ERR_INTERNAL_ERROR,
- _("Failed to find path for %s binary"),
- SYSINFO_SMBIOS_DECODER);
- return NULL;
+ return virCPUInfoSysinfoRead();
}
cmd = virCommandNewArgList(path, "-q", "-t",
"0,1,4,17", NULL);
Hi Prerna,
that sounds like a good idea, and the patch seems to work but I have
doubt with the usefulness in its current form. Let me explain:
with dmidecode available on my system I get:
...
<processor>
<entry name='socket_destination'>Socket 775</entry>
<entry name='type'>Central Processor</entry>
<entry name='family'>Other</entry>
<entry name='manufacturer'>Intel</entry>
<entry name='signature'>Type 0, Family 6, Model 15, Stepping
11</entry>
<entry name='version'>Intel(R) Core(TM)2 Duo CPU E6550 @
2.33GHz</entry>
<entry name='external_clock'>333 MHz</entry>
<entry name='max_speed'>4000 MHz</entry>
<entry name='status'>Populated, Enabled</entry>
</processor>
...
without dmidecode and your patch plugged in I get
<processor>
<entry name='socket_destination'>0</entry>
<entry name='type'>Intel(R) Core(TM)2 Duo CPU E6550 @
2.33GHz</entry>
<entry name='family'>6</entry>
<entry name='manufacturer'>GenuineIntel</entry>
</processor>
<processor>
<entry name='socket_destination'>1</entry>
<entry name='type'>Intel(R) Core(TM)2 Duo CPU E6550 @
2.33GHz</entry>
<entry name='family'>6</entry>
<entry name='manufacturer'>GenuineIntel</entry>
</processor>
so basically we get informations, some are available in both case but
differently, and worse, in the fallback case we get 2 physical processor
entries (I have only one) which is of course different from the single
processor that we get with dmidecode.
So 1/ is seems to me the fallback data can't be parsed
programmatically as a replacement of the original ones
2/ the data may be misunderstood and lead to erroneous
decision for example a schedule may start to stack 2 time more
load on my machine based on the difference of report.
So I'm a bit worried about applying it as-is, I'm afraid we need
to reconcile the output (as much as possible considering there
is less data) between both cases.
That said I think patch 1/2 looks fine to me, and could probably be
applied as-is,
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel(a)veillard.com | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/