02-23-2010
I'm trying to achieve the following goals:
1. Only read the log files from disk once.
2. Only decompress the log files once.
3. Process the log files with multiple parallel processes.
4. wait for them all to complete
5. do something else.
The reason being is that disk io and decompression are expensive in comparison to log processing, so I only want to do them once. And running the processing in parallel leverages my quad core processor to further reduce run time.
I think I have what I need, but I'm open to any other suggestions for how to do this better.
With background jobs method you suggest I would have to :
1. create an array of 6 unique temporary pipe names
2. mkfifo for each of the 6 pipes
3. start sending the decompressed logs to 6 named pipes using tee
4. launch a the 6 processing pipelines in the background telling them to read from the named pipes.
5. Now I could use wait to wait for them all.
6. rm all the temporary pipes
7. continue my script
This would work too, but is this better than using 'tee >(cmd1) >(cmd2)...>(cmd6)' and waiting for them to echo something into one named pipe that I have to manually manage? At least 'tee' takes care of creating and destroying the named pipes for me.
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LEARN ABOUT DEBIAN
pfsinmulti
pfsinmulti(1) General Commands Manual pfsinmulti(1)
NAME
pfsinmulti - read several streams of frames and write pfs streams to named pipes
SYNOPSIS
pfsinmulti pfsinmulti <file> [--frames f:s:t] [--skip-frames] [<file>...] -- command @1 @2 [@3 ...]
DESCRIPTION
Use this command to read several animation sequences and write them to pfsstreams. This command is useful with those pfs programs, which
take several pfs streams as arguments. For example, the following command can be used to combine two animations so that there are stitched
together:
pfsinmulti anim_a-%04d.hdr anim_b-%04d.hdr -- pfscat @1 @2
arguments @1 and @2 are replaced with named pipes for anim_a-%04d.hdr and anim_b-%04d.hdr frames respectively. command argument is obliga-
tory and it must be preceded with '--'. There should be as many @1, @2, .., @n arguments as there are animation sequences given as input.
Arguments --frames, --skip-frames and other options are handled the same way as in pfsin program. Also pfsinmulti recognizes the same file
formats as pfsin.
Technically, pfsinmulti creates a named pipe for each pfsstream, replaces @n arguments with the names of those pipes and deletes the pipes
when command finishes.
EXAMPLES
pfsinmulti image1.hdr image2.hdr -- cat @1 @2 | pfsview
Does the same as 'pfsv image1.hdr image2.hdr' but in much more sophisticated way.
SEE ALSO
pfsin(1)
BUGS
This command currently does not handle multiple frames given with a %d pattern in case of LDR formats: JPEG, PNG, PNM.
Please report bugs and comments to Rafal Mantiuk <mantiuk@mpi-sb.mpg.de>.
pfsinmulti(1)