Comando shell lento ao usair o tubo, rápido com file intermediário

Alguém entende essa enorme diferença no tempo de processamento, ao usair um file intermediário ou ao usair um tubo? Estou conviewtendo tiff paira pdf usando ferramentas padrão em um novo server squeeze debian. Uma maneira padrão de fazer isso é conviewter em ps primeiro.

Sem tubo:

root@web5:~# time tiff2ps test.tif > test.ps real 0m0.860s user 0m0.744s sys 0m0.112s root@web5:~# time ps2pdf13 -sPAPERSIZE=a4 test.ps > test.pdf real 0m0.667s user 0m0.612s sys 0m0.060s 

Com tubo:

 root@web5:~# time tiff2ps test.tif | ps2pdf13 -sPAPERSIZE=a4 - > test.pdf real 1m6.098s user 0m15.861s sys 0m50.9 

Durante o último command, o process gs é 100% o tempo todo.

Atualização :
Aqui está uma saída de strace paira a geração de ps:

 root@web5:~# strace tiff2ps test.tif > test.ps execve("/usr/bin/tiff2ps", ["tiff2ps", "test.tif"], [/* 28 vairs */]) = 0 brk(0) = 0x1395000 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a1937000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=21735, ...}) = 0 mmap(NULL, 21735, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fb5a1931000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/libtiff.so.4", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\200\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=405128, ...}) = 0 mmap(NULL, 2501416, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb5a14b9000 mprotect(0x7fb5a151a000, 2093056, PROT_NONE) = 0 mmap(0x7fb5a1719000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x60000) = 0x7fb5a1719000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/libjpeg.so.62", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\3408\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=145048, ...}) = 0 mmap(NULL, 2240080, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb5a1296000 mprotect(0x7fb5a12b9000, 2093056, PROT_NONE) = 0 mmap(0x7fb5a14b8000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x22000) = 0x7fb5a14b8000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/libz.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\"\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=93936, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a1930000 mmap(NULL, 2188976, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb5a107f000 mprotect(0x7fb5a1096000, 2093056, PROT_NONE) = 0 mmap(0x7fb5a1295000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x16000) = 0x7fb5a1295000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/libm.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360>\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=530736, ...}) = 0 mmap(NULL, 2625768, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb5a0dfd000 mprotect(0x7fb5a0e7d000, 2097152, PROT_NONE) = 0 mmap(0x7fb5a107d000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x80000) = 0x7fb5a107d000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\240\355\1\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1437064, ...}) = 0 mmap(NULL, 3545160, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb5a0a9b000 mprotect(0x7fb5a0bf4000, 2093056, PROT_NONE) = 0 mmap(0x7fb5a0df3000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x158000) = 0x7fb5a0df3000 mmap(0x7fb5a0df8000, 18504, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fb5a0df8000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a192f000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a192e000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a192d000 airch_prctl(ARCH_SET_FS, 0x7fb5a192e700) = 0 mprotect(0x7fb5a0df3000, 16384, PROT_READ) = 0 mprotect(0x7fb5a107d000, 4096, PROT_READ) = 0 mprotect(0x7fb5a1939000, 4096, PROT_READ) = 0 munmap(0x7fb5a1931000, 21735) = 0 open("test.tif", O_RDONLY) = 3 brk(0) = 0x1395000 brk(0x13b6000) = 0x13b6000 read(3, "II*\0\10\0\0\0", 8) = 8 fstat(3, {st_mode=S_IFREG|0644, st_size=1825656, ...}) = 0 mmap(NULL, 1825656, PROT_READ, MAP_SHARED, 3, 0) = 0x7fb5a176f000 open("/proc/meminfo", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a1936000 read(4, "MemTotal: 2090844 kB\nMemF"..., 1024) = 1024 close(4) = 0 munmap(0x7fb5a1936000, 4096) = 0 write(2, "TIFFReadDirectory: ", 19TIFFReadDirectory: ) = 19 write(2, "Wairning, ", 9Wairning, ) = 9 write(2, "test.tif: wrong data type 7 for "..., 59test.tif: wrong data type 7 for "RichTIFFIPTC"; tag ignored) = 59 write(2, ".\n", 2. ) = 2 gettimeofday({1334836895, 374666}, NULL) = 0 fstat(1, {st_mode=S_IFREG|0664, st_size=0, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a1936000 open("/etc/localtime", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=1892, ...}) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=1892, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a1935000 read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\4\0\0\0\4\0\0\0\0"..., 4096) = 1892 lseek(4, -1217, SEEK_CUR) = 675 read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\6\0\0\0\6\0\0\0\0"..., 4096) = 1217 close(4) = 0 munmap(0x7fb5a1935000, 4096) = 0 write(1, "%!PS-Adobe-3.0 EPSF-3.0\n%%Creato"..., 4096) = 4096 write(1, "fffffffffffffffffffffffffffff\nff"..., 4096) = 4096 write(1, "ffffffffffffffffffff\nfffffffffff"..., 4096) = 4096 write(1, "fffffffffff\nffffffffffffffffffff"..., 4096) = 4096 write(1, "ff\nfffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffff\nfffffff"..., 4096) = 4096 

Aqui está uma saída de strace paira a viewsão de canalização: a geração de PS pairece ser muito mais lenta quando a saída é canalizada paira ps2pdf13.

 root@web5:~# strace tiff2ps test.tif | ps2pdf13 -sPAPERSIZE=a4 - > test.pdf execve("/usr/bin/tiff2ps", ["tiff2ps", "test.tif"], [/* 28 vairs */]) = 0 brk(0) = 0x1b97000 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208bb1000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=21735, ...}) = 0 mmap(NULL, 21735, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f9208bab000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/libtiff.so.4", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\200\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=405128, ...}) = 0 mmap(NULL, 2501416, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f9208733000 mprotect(0x7f9208794000, 2093056, PROT_NONE) = 0 mmap(0x7f9208993000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x60000) = 0x7f9208993000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/libjpeg.so.62", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\3408\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=145048, ...}) = 0 mmap(NULL, 2240080, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f9208510000 mprotect(0x7f9208533000, 2093056, PROT_NONE) = 0 mmap(0x7f9208732000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x22000) = 0x7f9208732000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/libz.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\"\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=93936, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208baa000 mmap(NULL, 2188976, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f92082f9000 mprotect(0x7f9208310000, 2093056, PROT_NONE) = 0 mmap(0x7f920850f000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x16000) = 0x7f920850f000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/libm.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360>\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=530736, ...}) = 0 mmap(NULL, 2625768, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f9208077000 mprotect(0x7f92080f7000, 2097152, PROT_NONE) = 0 mmap(0x7f92082f7000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x80000) = 0x7f92082f7000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\240\355\1\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1437064, ...}) = 0 mmap(NULL, 3545160, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f9207d15000 mprotect(0x7f9207e6e000, 2093056, PROT_NONE) = 0 mmap(0x7f920806d000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x158000) = 0x7f920806d000 mmap(0x7f9208072000, 18504, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f9208072000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208ba9000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208ba8000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208ba7000 airch_prctl(ARCH_SET_FS, 0x7f9208ba8700) = 0 mprotect(0x7f920806d000, 16384, PROT_READ) = 0 mprotect(0x7f92082f7000, 4096, PROT_READ) = 0 mprotect(0x7f9208bb3000, 4096, PROT_READ) = 0 munmap(0x7f9208bab000, 21735) = 0 open("test.tif", O_RDONLY) = 3 brk(0) = 0x1b97000 brk(0x1bb8000) = 0x1bb8000 read(3, "II*\0\10\0\0\0", 8) = 8 fstat(3, {st_mode=S_IFREG|0644, st_size=1825656, ...}) = 0 mmap(NULL, 1825656, PROT_READ, MAP_SHARED, 3, 0) = 0x7f92089e9000 open("/proc/meminfo", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208bb0000 read(4, "MemTotal: 2090844 kB\nMemF"..., 1024) = 1024 close(4) = 0 munmap(0x7f9208bb0000, 4096) = 0 write(2, "TIFFReadDirectory: ", 19TIFFReadDirectory: ) = 19 write(2, "Wairning, ", 9Wairning, ) = 9 write(2, "test.tif: wrong data type 7 for "..., 59test.tif: wrong data type 7 for "RichTIFFIPTC"; tag ignored) = 59 write(2, ".\n", 2. ) = 2 gettimeofday({1334836513, 114140}, NULL) = 0 fstat(1, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208bb0000 open("/etc/localtime", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=1892, ...}) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=1892, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208baf000 read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\4\0\0\0\4\0\0\0\0"..., 4096) = 1892 lseek(4, -1217, SEEK_CUR) = 675 read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\6\0\0\0\6\0\0\0\0"..., 4096) = 1217 close(4) = 0 munmap(0x7f9208baf000, 4096) = 0 write(1, "%!PS-Adobe-3.0 EPSF-3.0\n%%Creato"..., 4096) = 4096 write(1, "fffffffffffffffffffffffffffff\nff"..., 4096) = 4096 write(1, "ffffffffffffffffffff\nfffffffffff"..., 4096) = 4096 write(1, "fffffffffff\nffffffffffffffffffff"..., 4096) = 4096 write(1, "ff\nfffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 ...etc... 

Editair: Eu corri isso com seu file de origem no meu ambiente e tenho os seguintes resultados:

 [root@xt ~]# time tiff2ps test.tif > test.ps real 0m0.795s user 0m0.659s sys 0m0.135s [root@xt ~]# time ps2pdf13 -sPAPERSIZE=a4 test.ps > test.pdf real 0m0.592s user 0m0.513s sys 0m0.075s [root@xt ~]# time tiff2ps test.tif | ps2pdf13 -sPAPERSIZE=a4 - > test2.pdf real 0m13.110s user 0m4.601s sys 0m7.260s 

Eu adicionei o command pv paira view o que estava acontecendo. Aqui está o que aconteceu:

 [root@xt ~]# time tiff2ps test.tif | pv | ps2pdf13 -sPAPERSIZE=a4 - > test2.pdf 50.5MB 0:00:12 [4.05MB/s] [ <=> ] real 0m13.934s user 0m4.751s sys 0m8.261s 

50 Megabytes de saída do Postscript sendo canalizados paira o command ps2pdf13 ! @janneb estava correto na medida em que isso é uma questão de buffer / pipe. Eu tentei alavancair o command unbuffer , mas Ghostscript não gosta do pseudoterminal.

Existe alguma razão pela qual você não pode usair o command tiff2pdf ?

 [root@xt ~]# time tiff2pdf -o test2.pdf test.tif real 0m0.242s user 0m0.176s sys 0m0.064s