File kdump-multithreading-by-default.patch of Package kdump.21349
From: Petr Tesarik <ptesarik@suse.com>
Date: Fri Jun 23 13:47:28 2017 +0200
Subject: Multithreading by default
References: bsc#1036223
Upstream: v0.8.17
Git-commit: 07534f44546e37c65a08fe7fb093255fbca6cd30
The "--num-threads" and "--split" makedumpfile options are mutually
exclusive. Before multithreading was implemented, "--split" was the
only way to use any additional CPUs. It makes more sense to use
multithreading by default.
To use "--split", the SPLIT flag can be specified.
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
---
doc/man/kdump.5.txt.in | 16 +++++++++++-----
kdumptool/savedump.cc | 17 +++++++++++++++++
kdumptool/savedump.h | 1 +
sysconfig.kdump.in | 5 +++--
4 files changed, 32 insertions(+), 7 deletions(-)
--- a/doc/man/kdump.5.txt.in
+++ b/doc/man/kdump.5.txt.in
@@ -513,11 +513,17 @@ This is a space-separated list of flags
Because SFTP and FTP are not mounted, that option has no meaning when saving
the dump to SFTP and FTP.
-*NOSPLIT*::
- Disable the _--split_ option of *makedumpfile*(8). This option is normally
- added when KDUMP_CPUS>1, because otherwise the additional CPUs are idle.
- You can specify this flag to force the use of only one dumping process,
- regardless of the value of KDUMP_CPUS.
+*SPLIT*::
+ If KDUMP_CPUS>1, use the _--split_ option of *makedumpfile*(8) instead of
+ the default _--num-threads_.
+
+*SINGLE*::
+ Specify this flag to force the use of only one CPU for dumping, regardless
+ of the value of KDUMP_CPUS.
+ It disables the _--split_ and _--num-threads_ options of *makedumpfile*(8).
+
+ For compatibility with older versions, *NOSPLIT* is an alias for *SINGLE*.
+ Its use is deprecated.
*XENALLDOMAINS*::
When dumping a Xen virtualization host, *makedumpfile*(8) is normally
--- a/kdumptool/savedump.cc
+++ b/kdumptool/savedump.cc
@@ -291,11 +291,24 @@ void SaveDump::saveDump(const RootDirURL
cpus = syscpu.numOnline();
}
if (!config->kdumptoolContainsFlag("NOSPLIT") &&
+ !config->kdumptoolContainsFlag("SINGLE") &&
cpus > 1) {
if (!useElf)
m_split = cpus;
else
cerr << "Splitting ELF dumps is not supported." << endl;
+
+ if (config->kdumptoolContainsFlag("SPLIT")) {
+ if (!useElf)
+ m_split = cpus;
+ else
+ cerr << "Splitting ELF dumps is not supported." << endl;
+ } else {
+ if (!useElf)
+ m_threads = cpus - 1;
+ else
+ cerr << "Multithreading is unavailable for ELF dumps" << endl;
+ }
}
bool excludeDomU = false;
@@ -313,6 +326,10 @@ void SaveDump::saveDump(const RootDirURL
cmdline << "makedumpfile ";
if (m_split)
cmdline << "--split ";
+ if (m_threads) {
+ SystemCPU syscpu;
+ cmdline << "--num-threads " << m_threads << " ";
+ }
cmdline << config->MAKEDUMPFILE_OPTIONS.value() << " ";
cmdline << "-d " << config->KDUMP_DUMPLEVEL.value() << " ";
if (excludeDomU)
--- a/kdumptool/savedump.h
+++ b/kdumptool/savedump.h
@@ -113,6 +113,7 @@ class SaveDump : public Subcommand {
bool m_usedDirectSave;
bool m_useMakedumpfile;
unsigned long m_split;
+ unsigned long m_threads;
std::string m_crashtime;
std::string m_crashrelease;
std::string m_rootdir;
--- a/sysconfig.kdump.in
+++ b/sysconfig.kdump.in
@@ -271,14 +271,15 @@ KDUMP_POSTSCRIPT=""
#
KDUMP_COPY_KERNEL="yes"
-## Type: string(NOSPARSE,NOSPLIT,XENALLDOMAINS)
+## Type: string(NOSPARSE,SPLIT,SINGLE,XENALLDOMAINS)
## Default: ""
## ServiceRestart: kdump
#
# Space-separated list of flags to tweak the run-time behaviour of kdumptool:
#
# NOSPARSE disable creation of sparse files.
-# NOSPLIT do not pass "--split" to makedumpfile even if KDUMP_CPUS > 1
+# SPLIT split the dump file with "makedumpfile --split"
+# SINGLE use single CPU to save the dump
# XENALLDOMAINS do not filter out Xen DomU pages
#
# See also: kdump(5).
