I am trying to inspect the difference between 2 perf reports before and after I apllied a patch. The patch certainly has new stack calls, and some of the old logic is removed. However, when I do perf diff old.data new.data, I am getting only the difference in time/cycles for objects which are in both files. How to see truely all differences? I could not find that in the man page.
I manually tried diff and comm, but the binary files produces from perf seem like no-go for these commands.
Related
I'm having trouble monitoring a file for changes. I need to be able to know when a file changes, and when it does, I need the new line that was added. I intend to parse each line and find ones that match certain criteria, and act on information in those lines. I know the expected number of matching lines ahead of time, but I do not know how many lines in total will be added to the file, or where the matching lines will be.
I've tried 2 packages so far, with no avail.
fsnotify/fsnotify
As fas as I can tell, fsnotify can only tell me when a file is modified, not what the details of the modification was. Since I need to know what exactly was added to the file, this is no good for me.
(As a side-question, can this be run in a loop? The example that I tried exited after just one modification. I need to monitor for multiple modifications.)
hpcloud/tail
This package tries to mimic the Unix tail command, but it seems to have its own issues. The output that I get includes timestamps and other data - I just want the added line, nothing else. Also, it seems to think a file has been modified multiple times, even when it's just one edit. Further, the deal breaker here is that it does not output the last line if the line was not followed by a newline character.
Delegating to tail
I came across this answer, which suggests to delegate this work to the tail command itself, but I need this to work cross-platform (specifically, macOS, Linux and Windows). I don't believe that an equivalent command exists on Windows.
How do I go about tackling this?
#user2515526,
Usually changed diff is out of scope of file watchers' functionality, because, you know, you could change an image, and a watcher would need to keep a track several Mb of a diff in memory, and what if we have thousands of files?
However, as bad as it sounds, this may be exactly the way you want to implement this (sure, depends on your app, etc. - could be fine for text files), i.e. - keeping a map of diffs (1 diff per file) since last modification. Cannot say I like it, but sounds like fsnotify has no support for changes/diffs that you need.
Also, regarding your question about running in a loop, maybe you can get some hints here: https://github.com/kataras/iris/blob/8370d76910cdd8de043753ed81ae080eae8dc798/utils/file.go
Its a framework that allows to build a server that watches for TypeScript file changes. So sounds similar to your case/question.
Cheers,
-D
I have a relatively simple bash script that reads from a set of static input files, stores the input in bash variables and then does a bunch of processing over said input by calling out to external scripts (e.g. written in Python, Go, other bash scripts etc.) and using the intermediate results.
Lately I have been experiencing an intermittent problem where a single character seems to be getting altered somewhere during the processing which then causes subsequent errors. Specifically, a lot of the processing I'm doing involves slicing up a list of comma-separated records, and one of the values on each line is a unix timestamp, e.g. 1354245000.
What seems to be happening is that occasionally one of these values will get altered slightly, so I end up with a timestamp like 13542458=2 or 13542458>2 or 13542458;2 coming out of one of the intermediate scripts. This then subsequently gets fed into another script, which throws an exception when it tries to parse the value to an integer.
In the title of this question, I've suggested that this might be a potential CPU/RAM error. I know the general folly in thinking errors are caused by low level things like hardware/compilers etcetera, but the nature of this particular error makes me think it may be possible, for the following reasons:
The input files are the same on each invocation of the script, and the script only fails on some invocations.
I cannot think of any sources of randomness in the source code prior to where the script is breaking. It's basically just slicing and dicing csv input.
I cannot think of any sources of concurrency in the source code -- even the Go scripts aren't actually written to run anything concurrently.
This problem has only arisen in the last week or so. Prior to this time, this error would never occur.
While I haven't documented every erroneous character, they seem to often be quite close in the ASCII table to numeric values (=, >, ; etc). That said, I guess the Hamming distance between two characters quite far apart can be small also with changes to a high order bit.
The script often breaks at a different stage on different runs. i.e. I have a number of separate Python scripts, and sometimes it'll make it past one script and then the error will be induced in another. Other times it'll be induced on an earlier script.
What I'd like to know is, is there any methodical way to either confirm or rule out a hardware error for this problem? Or if it is a hardware problem, is it possibly undetectable by the operating system?
A bit of further info on the machine:
Linux 64-bit, Ubuntu 12.04
Intel i7 processor
16GB DDR3 RAM
I'm hoping someone can either point me to a reliable way to verify whether the hardware is to blame or otherwise a sound reason as to what else might be the cause.
Try booting into Memtest to check your memory.
While it is highly unlikely that it will be hardware, if you have exhausted you standard software debug as suggested by #OliCharlesworth, here is an outline of hardware error investigation:
(1) check your log area for any `MCE` logs (machine check exceptions).
If you find any in either your log area (syslog) or sometimes in
the present working dir or /dir -- you have a hardware failure.
(2) check your log area for disk errors. e.g:
smartd[3963]: Device: /dev/sda [SAT], 34 Currently unreadable (pending) sectors
(3) check your drive integrity, e.g.: (as root) # `smartctl -a /dev/sda` if any abnormality, run:
smartctl -t short /dev/sda (change drive as required)
(4) download/install/boot to [memtest86](http://www.memtest86.com/download.htm)
(run the complete test)
If your cpu/motherboard has thrown no mce's, you have no disk error, your drive tests OK with smartctl and you have no memory errors with memtest86, then recheck the software debugging. While additional hardware errors can still be present (bad capacitors, etc..) the likelihood at this point is software. Good luck.
Want to upgrade my file management productivity by replacing 2 panel file manager with command line (bash or cygwin). Can commandline give same speed? Please advise a guru way of how to do e.g. copy of some file in directory A to the directory B. Is it heavy use of pushd/popd? Or creation of links to most often used directories? What are the best practices and a day-to-day routine to manage files of a command line master?
Can commandline give same speed?
My experience is that commandline copying is significantly faster (especially in the Windows environment). Of course the basic laws of physics still apply, a file that is 1000 times bigger than a file that copies in 1 second will still take 1000 seconds to copy.
..(howto) copy of some file in directory A to the directory B.
Because I often have 5-10 projects that use similar directory structures, I set up variables for each subdir using a naming convention :
project=NewMatch
NM_scripts=${project}/scripts
NM_data=${project}/data
NM_logs=${project}/logs
NM_cfg=${project}/cfg
proj2=AlternateMatch
altM_scripts=${proj2}/scripts
altM_data=${proj2}/data
altM_logs=${proj2}/logs
altM_cfg=${proj2}/cfg
You can make this sort of thing as spartan or baroque as needed to match your theory of living/programming.
Then you can easily copy the cfg from 1 project to another
cp -p $NM_cfg/*.cfg ${altM_cfg}
Is it heavy use of pushd/popd?
Some people seem to really like that. You can try it and see what you thing.
Or creation of links to most often used directories?
Links to dirs are, in my experience used more for software development where a source code is expecting a certain set of dir names, and your installation has different names. Then making links to supply the dir paths expected is helpful. For production data, is just one more thing that can get messed up, or blow up. That's not always true, maybe you'll have a really good reason to have links, but I wouldn't start out that way, just because it is possible to do.
What are the best practices and a day-to-day routine to manage files of a command line master?
( Per above, use standardized directory structure for all projects.
Have scripts save any small files to a directory your dept keeps in the /tmp dir, .
i.e /tmp/MyDeptsTmpFile (named to fit your local conventions) )
It depends. If you're talking about data and logfiles, dated fileNames can save you a lot of time. I recommend dateFmts like YYYYMMDD(_HHMMSS) if you need the extra resolution.
Dated logfiles are very handy, when a current process seems like it is taking a long time, you can look at the log file from a week ago and quantify exactly how long this process took, a week, month, 6 months (up to how much space you can afford). LogFiles should also capture all STDERR messages, so you never have to re-run a bombed program just to see what the error message was.
This is Linux/Unix you're using, right? Read the man page for the cp cmd installed on your machine. I recommend using an alias like alias CP='/bin/cp -pi' so you always copy a file with the same permissions and with the original files' time stamp. Then it is easy to use /bin/ls -ltr to see a sorted list of files with the most recent files showing up at the bottom of the list. (No need to scroll back to the top, when you sort by time,reverse). Also the '-i' option will warn you that you are going to overwrite a file, and this has saved me more than a couple of times.
I hope this helps.
P.S. as you appear to be a new user, if you get an answer that helps you please remember to mark it as accepted, and/or give it a + (or -) as a useful answer.
I am working on a script that has become fairly convoluted. I suspect there are several sections that have nearly identical code. Can I (and how can I) open the file in vim, with two (or more) windows on the buffer, and diff the contents of the windows on the same file? vimdiff seems to work only on two files. If I make a copy of the file and try to vimdiff the two versions, the diff origin remains locked on the beginning of the file. Although I can unscroll-lock the windows, and move the windows to the parts of the file I want to compare the diffs do not show up. Any hints or tips? I could cut and paste the sections I want to compare to different files and then apply vimdiff but then I risk getting lost in what section came from where when I try to patch the separate files together, and I feel sure there must be a more straightforward, easier way.
What I usually do is diff to a copy
:%w %.alt
:vert diffsplit %.alt
And then happiliy rearrange the 'alt' version so that the pseudo-matching bits get aligned.
Note that (presumably) git contains spiffy merge/diff cow-powers that should be able to detect sub-file moved block changes.
Although I haven't (yet) actually put this into practice, I have a hunch that the very nice git plugin fugitive for vim might be able to leverage some of this horsepower to make this easier. Note: fully expect this to require scriptinh before being usable, but I still thought it would be nice to share this idea (perhaps you can share a script if you get to it first!)
As an alternative solution that I've been using occasionally and which works very nicely in my opinion is linediff.vim.
It allows you to use visual mode to select two bodies of text from arbitrary buffers (or the same for that matter) and run vimdiff on them. The beauty of it, is that when you edit and save the temporary diff buffers, you update the original buffers with the changes, without saving.
One of my use-cases is when I'm resolving merge issues related to script refactoring and reordering, where a function has been moved and perhaps also modified. In order to make sure you do not lose any of the modifications coming in from either ancestor, you diff the two versions of the function alone by visually selecting them and running the linediff command.
I am using JMeter and have 2 questions (I have read the FAQ + Wiki etc):
I use the Graph Results listener. It seems to have a fixed span, e.g. 2 hours (just guessing - this is not indicated anywhere AFAIK), after which it wraps around and starts drawing on same canvas from the left again. Hence after a long weekend run it only shows the results of last 2 hours. Can I configure that span or other properties (beyond the check boxes I see on the Graph Results listener itself)?
Can I save the results of a run and later open them? I know I can save the test plan or parts of it. I am unclear if I can save separately just the test results data, and later open them and perform comparisons etc. And furthermore can I open them with different listeners even if they weren't part of original test (i.e. I think of the test as accumulating data, and later on I want to view and interpret the data using different "viewers").
Thanks,
-- Shaul
Don't know about 1. Regarding 2: listeners typically have a configuration field for "Write All Data to a File", which lets you specify the file name. You can use the Simple Data Writer to store results efficiently for later analysis.
You can load results from a previous test into a visualizer by choosing "Write All Data to a File" and browsing for the file you wish to load. Somewhat counterintuitively, selecting a file for writing also loads that file into the visualizer and displays the results. Just make sure you don't run the test again while that file is selected, otherwise you will lose your saved test data. :-)
Well, I later found a JMeter group that was discussing the issue raised in my first question, and B.Ramann gave me an excellent suggestion to use instead a better graph found here.
-- Shaul