We are facing a memory fragmentation issue in our 32 bit app (C++ and WPF based). when we run it for 100 hrs. as part of automated test. Application crashes after running AST for ~14 hrs.
We use CRT heap with LFH policy (Low fragment Heap) exclusively enabled in Main(). Problem is coming on windows 10 platform. No issue on Windows 8 platform with same set of our application binaries. We completed 100 hrs. run for test in windows 8 platform.
We create a large block heap in Main() method and this heap we use for specific purpose when we need a large amount of memory and we are managing it in our code. From Virtual Memory Statistics logs we can see that initial virtual memory allocation is 1.79 GB.
After 14 hrs. of automated test run : on windows 10
Combined Available = 1590176752( 1516.511 MB)
Combined Max Available = 3989504( 3.805 MB)
Combined Frag Percent = 99.75%
CRT:sum_alloc = 2737569144(98.50%, 2610.749 MB)
CRT:max_alloc = 4458496( 4.252 MB)
CRT:allocAverageSize = 9043
CRT:num_free_blocks = 37813
CRT:sum_free = 22620888( 0.81%, 21.573 MB)
CRT:max_free = 514104( 0.490 MB)
VM:sum_free = 1581957120(36.83%,1508.672 MB)
VM:max_free = 10321920( 9.844 MB)
On windows 8 for 100 hrs.
Combined Available = 1881204960( 1794.057 MB)
Combined Max Available = 1734127616( 1653.793 MB)
Combined Frag Percent = 7.82%
VM:sum_free = 1845817344(42.98%,1760.309 MB)
VM:max_free = 1734127616( 1653.793 MB)
We are using ADPlus and (debugging tools for Windows, Windbg and DebugDiag) tool to collect memory dumps at interval of 3 hrs.
Is there any setting or flag which I need to enable or anything I have to do withy code, using VS2010.
Application is based on Windows 10 LTSB 64 bit (which is very specific Enterprise OS version for windows 10, gives stability and security)
Related
I'm running three Java 8 JVMs on a 64 bit Ubuntu VM which was built from a minimal install with nothing extra running other than the three JVMs. The VM itself has 2GB of memory and each JVM was limited by -Xmx512M which I assumed would be fine as there would be a couple of hundred MB spare.
A few weeks ago, one crashed and the hs_err_pid dump showed:
# There is insufficient memory for the Java Runtime Environment to continue.
# Native memory allocation (mmap) failed to map 196608 bytes for committing reserved memory.
# Possible reasons:
# The system is out of physical RAM or swap space
# In 32 bit mode, the process size limit was hit
# Possible solutions:
# Reduce memory load on the system
# Increase physical memory or swap space
# Check if swap backing store is full
# Use 64 bit Java on a 64 bit OS
# Decrease Java heap size (-Xmx/-Xms)
# Decrease number of Java threads
# Decrease Java thread stack sizes (-Xss)
# Set larger code cache with -XX:ReservedCodeCacheSize=
# This output file may be truncated or incomplete.
I restarted the JVM with a reduced heap size of 384MB and so far everything is fine. However when I currently look at the VM using the ps command and sort in descending RSS size I see
RSS %MEM VSZ PID CMD
708768 35.4 2536124 29568 java -Xms64m -Xmx512m ...
542776 27.1 2340996 12934 java -Xms64m -Xmx384m ...
387336 19.3 2542336 6788 java -Xms64m -Xmx512m ...
12128 0.6 288120 1239 /usr/lib/snapd/snapd
4564 0.2 21476 27132 -bash
3524 0.1 5724 1235 /sbin/iscsid
3184 0.1 37928 1 /sbin/init
3032 0.1 27772 28829 ps ax -o rss,pmem,vsz,pid,cmd --sort -rss
3020 0.1 652988 1308 /usr/bin/lxcfs /var/lib/lxcfs/
2936 0.1 274596 1237 /usr/lib/accountsservice/accounts-daemon
..
..
and the free command shows
total used free shared buff/cache available
Mem: 1952 1657 80 20 213 41
Swap: 0 0 0
Taking the first process as an example, there is an RSS size of 708768 KB even though the heap limit would be 524288 KB (512*1024).
I am aware that extra memory is used over the JVM heap but the question is how can I control this to ensure I do not run out of memory again ? I am trying to set the heap size for each JVM as large as I can without crashing them.
Or is there a good general guideline as to how to set JVM heap size in relation to overall memory availability ?
There does not appear to be a way of controlling how much extra memory the JVM will use over the heap. However by monitoring the application over a period of time, a good estimate of this amount can be obtained. If the overall consumption of the java process is higher than desired, then the heap size can be reduced. Further monitoring is needed to see if this impacts performance.
Continuing with the example above and using the command ps ax -o rss,pmem,vsz,pid,cmd --sort -rss we see usage as of today is
RSS %MEM VSZ PID CMD
704144 35.2 2536124 29568 java -Xms64m -Xmx512m ...
429504 21.4 2340996 12934 java -Xms64m -Xmx384m ...
367732 18.3 2542336 6788 java -Xms64m -Xmx512m ...
13872 0.6 288120 1239 /usr/lib/snapd/snapd
..
..
These java processes are all running the same application but with different data sets. The first process (29568) has stayed stable using about 190M beyond the heap limit while the second (12934) has reduced from 156M to 35M. The total memory usage of the third has stayed well under the heap size which suggests the heap limit could be reduced.
It would seem that allowing 200MB extra non heap memory per java process here would be more than enough as that gives 600MB leeway total. Subtracting this from 2GB leaves 1400MB so the three -Xmx parameter values combined should be less than this amount.
As will be gleaned from reading the article pointed out in a comment by Fairoz there are many different ways in which the JVM can use non heap memory. One of these that is measurable though is the thread stack size. The default for a JVM can be found on linux using java -XX:+PrintFlagsFinal -version | grep ThreadStackSize In the case above it is 1MB and as there are about 25 threads, we can safely say that at least 25MB extra will always be required.
why GlobalMemoryStatusEx() gives huge total virtual memory.Does it take into account all the page files that can be created?
System details:
Windows 8.1, 64 bit Process, x64 Processor
int main()
{
MEMORYSTATUSEX mex;
mex.dwLength = sizeof (mex);
GlobalMemoryStatusEx(&mex);
std::cout<<mex.ullTotalVirtual<<" "<<mex.ullAvailVirtual;
}
140737488224256 140737478111232
EDIT:
I got same result on Windows 10.I am interested in knowing how this 127 TB figure comes up.Why does the system not take into account that i don't have 127 tb space on my disk?
A 32 bit process on (x64 system) shows only 2gb which is the accessible address limit of a 32 bit process for user mode.Why does it not take into account page files in case of 32 bit process?
Yes. From MSDN:
You can use the GlobalMemoryStatusEx() to determine how much memory your application can allocate without severely impacting other applications.
This question concerns the PERFORMANCE_INFORMATION struct from the Process Status API (PSAPI) on Windows.
From the documentation, I would assume that CommitTotal >= (PhysicalTotal - PhysicalAvailable) since CommitTotal also includes the page file in addition to physical memory.
However, on my system I get the following values that violate the assumption:
CommitTotal = 7,943,270,400 (~ 7.4 GB)
PhysicalTotal – PhysicalAvailable = 9,685,630,976 (~ 9 GB)
I am running a spark job, and I got Not enough space to cache rdd_128_17000 in memory warning. However, in the attached file, it obviously saying only 90.8 G out of 719.3 G is used. Why is that? Thanks!
15/10/16 02:19:41 WARN storage.MemoryStore: Not enough space to cache rdd_128_17000 in memory! (computed 21.4 GB so far)
15/10/16 02:19:41 INFO storage.MemoryStore: Memory use = 4.1 GB (blocks) + 21.2 GB (scratch space shared across 1 thread(s)) = 25.2 GB. Storage limit = 36.0 GB.
15/10/16 02:19:44 WARN storage.MemoryStore: Not enough space to cache rdd_129_17000 in memory! (computed 9.4 GB so far)
15/10/16 02:19:44 INFO storage.MemoryStore: Memory use = 4.1 GB (blocks) + 30.6 GB (scratch space shared across 1 thread(s)) = 34.6 GB. Storage limit = 36.0 GB.
15/10/16 02:25:37 INFO metrics.MetricsSaver: 1001 MetricsLockFreeSaver 339 comitted 11 matured S3WriteBytes values
15/10/16 02:29:00 INFO s3n.MultipartUploadOutputStream: uploadPart /mnt1/var/lib/hadoop/s3/959a772f-d03a-41fd-bc9d-6d5c5b9812a1-0000 134217728 bytes md5: qkQ8nlvC8COVftXkknPE3A== md5hex: aa443c9e5bc2f023957ed5e49273c4dc
15/10/16 02:38:15 INFO s3n.MultipartUploadOutputStream: uploadPart /mnt/var/lib/hadoop/s3/959a772f-d03a-41fd-bc9d-6d5c5b9812a1-0001 134217728 bytes md5: RgoGg/yJpqzjIvD5DqjCig== md5hex: 460a0683fc89a6ace322f0f90ea8c28a
15/10/16 02:42:20 INFO metrics.MetricsSaver: 2001 MetricsLockFreeSaver 339 comitted 10 matured S3WriteBytes values
This is likely to be caused by the configuration of spark.storage.memoryFraction being too low. Spark will only use this fraction of the allocated memory to cache RDDs.
Try either:
increasing the storage fraction
rdd.persist(StorageLevel.MEMORY_ONLY_SER) to reduce memory usage by serializing the RDD data
rdd.persist(StorageLevel.MEMORY_AND_DISK) to partially persist onto disk if memory limits are reached.
This could be due to the following issue if you're loading lots of avro files:
https://mail-archives.apache.org/mod_mbox/spark-user/201510.mbox/%3CCANx3uAiJqO4qcTXePrUofKhO3N9UbQDJgNQXPYGZ14PWgfG5Aw#mail.gmail.com%3E
With a PR in progress at:
https://github.com/databricks/spark-avro/pull/95
I have a Spark-based batch application (a JAR with main() method, not written by me, I'm not a Spark expert) that I run in local mode without spark-submit, spark-shell, or spark-defaults.conf. When I tried to use IBM JRE (like one of my customers) instead of Oracle JRE (same machine and same data), I started getting those warnings.
Since the memory store is a fraction of the heap (see the page that Jacob suggested in his comment), I checked the heap size: IBM JRE uses a different strategy to decide default heap size and it was too small, so I simply added appropriate -Xms and -Xmx params and the problem disappeared: now the batch works fine both with IBM and Oracle JRE.
My usage scenario is not typical, I know, however I hope this can help someone.
I'm usining Windows 7, 64bits, 8GB ram
I'm needing to make alloc more than 2GB but I'm getting runtime error
look at my piece of code
#define MAX_PESSOAS 30000000
int i;
double ** totalPessoas = new double *[MAX_PESSOAS];
for(i = 0; i < MAX_PESSOAS; i++)
totalPessoas[i] = new double [5];
MAX_PESSOAS is set to 30milion, but I'll need at least 1billion (ok, I know I'll need more than 8GB but nvm, I can get it, I only need to know how to do that )
I'm using visual studio 2012
If your application is building to a 64-bit binary, it can address more than 8 GB without any special steps.
If your application is building to a 32-bit binary, you can address up to 3 GB (or 4 GB if you're running 64-bit Windows) by enabling 4-gigabyte tuning, as long as the system supports it.
Your best bet is probably to compile your application as a 64-bit binary, if you know that the operating system it will be running on is 64-bit.