I need to find the virtual address size supported in my PC running Linux Ubuntu. Following is my kernel version:
$ uname -a
Linux ubuntu 2.6.28-11-generic #42-Ubuntu SMP Fri Apr 17 01:57:59 UTC 2009 i686 GNU/Linux
I also ran 'free' to know this, as per some earlier posts in this forum:
***#ubuntu:~$ free
total used free shared buffers cached
Mem: 2963968 740752 2223216 0 217648 360296
-/+ buffers/cache: 162808 2801160
Swap: 262136 0 262136
However, the value that I obtained is not a power of 2, as I had expected.
Please let me know the correct way to obtain the total virtual memory address space. Thanks in advance for your help.
Use following command
cat /proc/meminfo
You will get a list of information
You can seeVmallocTotal, is the size of total virtual memory allocated.
Related
Does linux make use of TLB when running as VM?
I wrote a C program to find 'Average access time per page' and found that with any number of frequent page access, the 'Average access time per page' is same.
For example,
With frequent access of 32 pages (10000000 times), its ~10 nano seconds.
With frequent access of 64 pages (10000000 times), its ~10 nano seconds.
With frequent access of 124 pages (10000000 times), its ~10 nano seconds.
With frequent access of 256 pages (10000000 times), its ~10 nano seconds.
With frequent access of 512 pages (10000000 times), its ~10 nano seconds.
and so on.
Does the above test reflect that linux does can not use TLB when running as a virtual machine and always goes to page table entry to get the translation for every 'virtual page number' to 'Physical page frame' for a process?
My machine details are:
[ ] uname -mpi
x86_64 x86_64 x86_64
[ ] getconf PAGE_SIZE
4096
[ ] uname -a
Linux VirtualBox 5.8.0-53-generic #60~20.04.1-Ubuntu SMP Thu May 6 09:52:46 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Thanks,
I used Spike to boot linux using the riscv tools but the linux boot sequence seems to stop at Bootconsole[early0] disabled.
I tried adding kernel command line root=/dev/vda ro console=ttyS0 but didn't work. The same console settings works in QEMU. Also checked the .config file for the line CONFIG_HVC_RISCV_SBI=y. It was there. Still coulnd't get past it.
Tried with Linux kernel version 4.19 to 5.2. No luck. Am I doing something wrong here?
Steps I followed:
Compiled linux with Riscv toolchain
compiled riscv-pk with ../configure --host=riscv64-unknown-elf --with-payload= [path to vmlinux]
used "Spike bbl" to start spike image.
Please let me know if any more info is required.
Sorry, noob here.
Attaching terminal output
bbl loader
OF: fdt: Ignoring memory range 0x80000000 - 0x80200000
Linux version 4.19.59 (root#AsusFX504) (gcc version 8.2.0 (GCC)) #2 SMP Sat Jul 20 05:11:32 IST 2019
bootconsole [early0] enabled
initrd not found or empty - disabling initrd
Zone ranges:
DMA32 [mem 0x0000000080200000-0x00000000ffffffff]
Normal empty
Movable zone start for each node
Early memory node ranges
node 0: [mem 0x0000000080200000-0x00000000ffffffff]
Initmem setup node 0 [mem 0x0000000080200000-0x00000000ffffffff]
software IO TLB: mapped [mem 0xfa3fe000-0xfe3fe000] (64MB)
elf_hwcap is 0x112d
percpu: Embedded 17 pages/cpu s29912 r8192 d31528 u69632
Built 1 zonelists, mobility grouping on. Total pages: 516615
Kernel command line:
Dentry cache hash table entries: 262144 (order: 9, 2097152 bytes)
Inode-cache hash table entries: 131072 (order: 8, 1048576 bytes)
Sorting __ex_table...
Memory: 1988760K/2095104K available (5468K kernel code, 329K rwdata, 1751K rodata, 193K init, 806K bss, 106344K reserved, 0K cma-reserved)
SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
rcu: Hierarchical RCU implementation.
rcu: RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=1.
rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=1
NR_IRQS: 0, nr_irqs: 0, preallocated irqs: 0
clocksource: riscv_clocksource: mask: 0xffffffffffffffff max_cycles: 0x24e6a1710, max_idle_ns: 440795202120 ns
Console: colour dummy device 80x25
console [tty0] enabled
bootconsole [early0] disabled
This might be because Virtual Terminal is enabled in your linux config. Disabling Virtual Terminal might solve your issue.
In Linux make menuconfig go to :-
Location:
-> Device Drivers
-> Character devices
and Disble Virtual terminal .
Symbol: VT [=y] n
Type : bool
Prompt: Virtual terminal
As mentioned previously, the reason is that VT is enabled so kernel has a dummy VT framebuffer that simply goes nowhere, but you don't have to disable it. console=ttyS0 will also not work, since SPIKE doesn't emulate it. Note that this won't work on the HiFive Unleashed, either, since serial terminals there are ttySIF0 and ttySIF1. What you want is console=hvc0 and SPIKE will be able to continue from there, e.g. in your kernel .config:
CONFIG_CMDLINE_BOOL=y
CONFIG_CMDLINE="earlyprintk console=hvc0"
CONFIG_CMDLINE_FORCE=y
I have an application that I eventually want to run on a cloud computing service (e.g., such as AWS or Google Cloud) packaged inside a docker image. The reason the application will need to run in the cloud is because it's designed to process large data files, but before I actually deploy, I'd like to test it first on a local laptop, using a single large data file that I've stored (for test and development purposes) on an external USB drive.
My development machine is an OSX laptop, and I'm using a recent version of docker:
stachyra> uname -a
Darwin Andrews-MacBook-Pro-76.local 14.5.0 Darwin Kernel Version 14.5.0: Tue Sep 1 21:23:09 PDT 2015; root:xnu-2782.50.1~1/RELEASE_X86_64 x86_64
stachyra> docker --version
Docker version 1.10.2, build c3959b1
OSX has mounted my external USB drive, device /dev/disk2s2, as /Volumes/MGR DATA:
stachyra> df
Filesystem 512-blocks Used Available Capacity iused ifree %iused Mounted on
/dev/disk1 974770480 435721376 538537104 45% 54529170 67317138 45% /
devfs 375 375 0 100% 650 0 100% /dev
map -hosts 0 0 0 100% 0 0 100% /net
map auto_home 0 0 0 100% 0 0 100% /home
/dev/disk2s2 3906291632 3869523640 36767992 100% 483690453 4595999 99% /Volumes/MGR DATA
/dev/disk3s1 196608 193160 3448 99% 24143 431 98% /Volumes/VirtualBox
stachyra> diskutil list
/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *500.3 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_CoreStorage 499.4 GB disk0s2
3: Apple_Boot Recovery HD 650.0 MB disk0s3
/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: Apple_HFS Macintosh HD *499.1 GB disk1
Logical Volume on disk0s2
DB70B91A-3B57-4C82-A758-C4BDEA4160FD
Unlocked Encrypted
/dev/disk2
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *2.0 TB disk2
1: EFI EFI 209.7 MB disk2s1
2: Apple_HFS MGR DATA 2.0 TB disk2s2
/dev/disk3
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *100.7 MB disk3
1: Apple_HFS VirtualBox 100.7 MB disk3s1
and it should also be noted, the drive has several directories and data which are visible inside it, at least when viewed directly through OSX:
stachyra> ls -l /Volumes/MGR\ DATA
total 0
drwxr-xr-x 6 stachyra staff 204 Apr 14 2015 1000genomes
drwxr-xr-x 5 stachyra staff 170 Oct 12 17:41 GIAB
drwxr-xr-x 4 stachyra staff 136 Apr 28 2015 genome_browser_tracks
drwxr-xr-x 24 stachyra staff 816 Oct 6 14:00 mitty
I have tried to follow the advice from this question, which describes how to mount a USB drive in docker when docker is running within a linux host. But my local laptop is OSX, not linux, so it doesn't seem to work.
Explicitly, when attempting to follow the advice of the accepted answer, I obtain the following result:
stachyra> docker run -i -t --privileged -v /dev/disk2s2:/dev/foo ubuntu bash
root#8da7b492a707:/# uname -a
Linux 8da7b492a707 4.1.18-boot2docker #1 SMP Sat Feb 20 08:24:27 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
root#8da7b492a707:/# ls -l /dev/foo
total 0
root#8da7b492a707:/#
Based upon the response, one can see that docker does indeed launch a linux container correctly, and it also creates a volume /dev/foo inside of the container as requested, but the actual contents of the USB drive are not accessible via that location--the ls -l command claims there are no files or directories there.
I also tried the second method described in an alternate response to the same question, and that fails even worse:
stachyra> docker run -i -t --device=/dev/disk2s2 ubuntu bash
docker: Error response from daemon: error gathering device information while adding custom device "/dev/disk2s2": not a device node.
stachyra>
I have found another discussion thread on stackoverflow which suggests that raw USB access is handled quite differently in OSX than in linux, which I suspect is probably the reason why both of the above attempts at USB access are failing.
But, what should I actually do about it? That is to say, what is the correct sequence of actions or commands to allow docker to access a USB device mounted on an OSX host, rather than linux?
I was finally able to access my USB drive from /var/media inside my container by using the machine-diskutil.sh script mentioned in warmoverflow's comment like so
machine-diskutil.sh mount my-machine-name /Volumes/my-usb-drive
and then starting the container like so
docker run -v /Volumes/my-usb-drive:/var/media -it my/image:latest bash
Because I had tried to add /Volumes/my-usb-drive as a shared folder manually in VirtualBox, I first got this error.
Error: The shared folder /Volumes/Seagate already exists on the
docker machine, please unmount it first.
So I removed it manually and re-ran the machine-diskutil.sh mount command without any problems. Great stuff!
As per #pgayvallet comment on GitHub:
As the daemon runs inside a VM in Docker Desktop, it is not possible to actually share a mac host device with the container inside the VM, and this will most definitely never be possible.
I have been running a tcpdump based script on Ubuntu for some time, and recently I have been asked to run it on CentOS 6.5 and I'm noticing some very interesting differences
I'm running tcpdump 4.6.2, libpcap 1.6.2 on both setups, both are actually running on the same hardware (dual booted)
I'm running the same command on both OS'.
sudo /usr/sbin/tcpdump -s 0 -nei eth9 -w /mnt/tmpfs/eth9_rx.pcap -B 2000000
From "free -k", I see about 2G allocated on Ubuntu
Before:
free -k
total used free shared buffers cached
Mem: 65928188 1337008 64591180 1164 26556 68596
-/+ buffers/cache: 1241856 64686332
Swap: 67063804 0 67063804
After:
free -k
total used free shared buffers cached
Mem: 65928188 3341680 62586508 1160 26572 68592
-/+ buffers/cache: 3246516 62681672
Swap: 67063804 0 67063804
expr 3341680 - 1337184
2004496
One CentOS, I see twice the amount of memory (4G) being allocated from the same command
Before:
free -k
total used free shared buffers cached
Mem: 16225932 394000 15831932 0 15308 85384
-/+ buffers/cache: 293308 15932624
Swap: 8183804 0 8183804
After:
free -k
total used free shared buffers cached
Mem: 16225932 4401652 11824280 0 14896 84884
-/+ buffers/cache: 4301872 11924060
Swap: 8183804 0 8183804
expr 4401652 - 394000
4007652
From the command, I'm listening against an interface and dumping into a RAMdisk.
On Ubuntu, I can capture packets at line rate for large size packets (10G, 1024 byte frames)
But on CentOS, I can only capture packets at 60% of line rate (10G, 1024 byte frames)
Also, both OS's are running the same version of NIC drivers and driver configurations.
My goal is to achieve the same performance on CentOS as I have with Ubuntu.
I googled around and there seems to be the magic of libpcap behaving differently with different kernels. I'm curious if there's any kernel side options I have to tweek on the CentOS side to achieve the same performance on Ubuntu.
This has been answered. According to Guy Harris from tcpdump/libpcap, the difference is due to CentOS6.5 running 2.6.X kernel. Below is his response:
"
3.2 introduced the TPACKET_V3 version of the "T(urbo)PACKET" memory-mapped packet capture mechanism for PF_PACKET sockets; newer versions of libpcap (1.5 and later) support TPACKET_V3 and will use it if the kernel supports it. TPACKET_V3 makes much more efficient use of the capture buffer; in at least one test, it dropped fewer packets. It also might impose less overhead, so that asking for a 2GB buffer takes less kernel memory."
I have made JavaFx application which is running fine in Window , Mac OS but when i run in Linux Fedora the application make crash the whole system with the following log.
1) What is the reason of crash in Linux ?
2) What may the be the possible solution of this crash?
A fatal error has been detected by the Java Runtime Environment:
SIGSEGV (0xb) at pc=0x00840e58, pid=2114, tid=2694839152 JRE version:
Java(TM) SE Runtime Environment (7.0_51-b13) (build 1.7.0_51-b13)
Java VM: Java HotSpot(TM) Client VM (24.51-b03 mixed mode linux-x86 )
Problematic frame: C [libc.so.6+0x2fe58] exit+0x38 Failed to write
core dump. Core dumps have been disabled. To enable core dumping, try
"ulimit -c unlimited" before starting Java again If you would like to
submit a bug report, please visit:
http://bugreport.sun.com/bugreport/crash.jsp The crash happened
outside the Java Virtual Machine in native code. See problematic
frame for where to report the bug.
--------------- T H R E A D ---------------
Current thread (0xa0a8d800): JavaThread "JNativeHook Native Hook"
[_thread_in_native, id=2306, stack(0xa01ff000,0xa0a00000)]
--------------- S Y S T E M ---------------
OS:Fedora release 14 (Laughlin)
uname:Linux 2.6.35.6-45.fc14.i686 #1 SMP Mon Oct 18 23:56:17 UTC 2010
i686 libc:glibc 2.12.90 NPTL 2.12.90 rlimit: STACK 8192k, CORE 0k,
NPROC 1024, NOFILE 1024, AS infinity load average:20.56 6.52 4.06
/proc/meminfo: MemTotal: 1013996 kB MemFree: 112652 kB
Buffers: 4224 kB Cached: 140000 kB
Memory: 4k page, physical 1013996k(112652k free), swap
1535996k(665220k free)
vm_info: Java HotSpot(TM) Client VM (24.51-b03) for linux-x86 JRE
(1.7.0_51-b13), built on Dec 18 2013 18:49:34 by "java_re" with gcc
4.3.0 20080428 (Red Hat 4.3.0-8)
time: Mon Feb 10 16:29:44 2014 elapsed time: 15804 seconds
I am not entering the whole log because it is too long to post. please provide possible solution of Exception log
Please file a bug at https://github.com/kwhat/jnativehook with the entire crash log. Chances are the issue has already been fixed in the 1.2 trunk.