255
is out of order with respect to
memory store
of size 1 at address 0x7FD7BEBC068F (offset 0x3C068F in /mnt/pmem/file)
in /data/listing_12-38!main at listing_12-38.cpp:98 - 0x1DAF
in /lib64/libc.so.6!__libc_start_main at:
- 0x223D3
in /data/listing_12-38!_start at: - 0x1624
The Persistence Inspector report identifies an out-of-order store issue. The tool
says that incrementing the counter in line 91 (main at listing_12-38.cpp:91) is
out of order with respect to writing the valid flag inside a record in line 98 (main at
listing_12-38.cpp:98).
To perform out-of-order analysis with pmemcheck, we must introduce a new tool
called pmreorder. The pmreorder tool is included in PMDK from version 1.5 onward.
This stand- alone Python tool performs a consistency check of persistent programs
using a store reordering mechanism. The pmemcheck tool cannot do this type of analysis,
although it is still used to generate a detailed log of all the stores and flushes issued by an
application that pmreorder can parse. For example, consider Listing 12-41.
Listing 12-41. Running pmemcheck to generate a detailed log of all the stores
and flushes issued by Listing 12-38
$ valgrind --tool=pmemcheck -q --log-stores=yes --log-storesstacktraces=yes
--log-stores-stacktraces-depth=2 --print-summary=yes
--log-file=store_log.log ./listing_12-38
The meaning of each parameter is as follows:
• -q silences unnecessary pmemcheck logs that pmreorder cannot parse.
• --log-stores=yes tells pmemcheck to log all stores.
• --log-stores-stacktraces=yes dumps stacktrace with each logged
store. This helps locate issues in your source code.
• --log-stores-stacktraces-depth=2 is the depth of logged
stacktraces. Adjust according to the level of information you need.
Chapter 12 Debugging persistent MeMory appliCations
is out of order with respect to
memory store
of size 1 at address 0x7FD7BEBC068F (offset 0x3C068F in /mnt/pmem/file)
in /data/listing_12-38!main at listing_12-38.cpp:98 - 0x1DAF
in /lib64/libc.so.6!__libc_start_main at
- 0x223D3
in /data/listing_12-38!_start at
The Persistence Inspector report identifies an out-of-order store issue. The tool
says that incrementing the counter in line 91 (main at listing_12-38.cpp:91) is
out of order with respect to writing the valid flag inside a record in line 98 (main at
listing_12-38.cpp:98).
To perform out-of-order analysis with pmemcheck, we must introduce a new tool
called pmreorder. The pmreorder tool is included in PMDK from version 1.5 onward.
This stand- alone Python tool performs a consistency check of persistent programs
using a store reordering mechanism. The pmemcheck tool cannot do this type of analysis,
although it is still used to generate a detailed log of all the stores and flushes issued by an
application that pmreorder can parse. For example, consider Listing 12-41.
Listing 12-41. Running pmemcheck to generate a detailed log of all the stores
and flushes issued by Listing 12-38
$ valgrind --tool=pmemcheck -q --log-stores=yes --log-storesstacktraces=yes
--log-stores-stacktraces-depth=2 --print-summary=yes
--log-file=store_log.log ./listing_12-38
The meaning of each parameter is as follows:
• -q silences unnecessary pmemcheck logs that pmreorder cannot parse.
• --log-stores=yes tells pmemcheck to log all stores.
• --log-stores-stacktraces=yes dumps stacktrace with each logged
store. This helps locate issues in your source code.
• --log-stores-stacktraces-depth=2 is the depth of logged
stacktraces. Adjust according to the level of information you need.
Chapter 12 Debugging persistent MeMory appliCations