> open("/usr/lib/python3.4/encodings/__pycache__/unicode_escape.cpython-34.pyc",
> O_RDONLY|O_CLOEXEC) = 8
> fstat(8, {st_mode=S_IFREG|0644, st_size=1842, ...}) = 0
> lseek(8, 0, SEEK_CUR) = 0
> fstat(8, {st_mode=S_IFREG|0644, st_size=1842, ...}) = 0
> read(8,
> "\356\f\r\n\240#5T\240\4\0\0\343\0\0\0\0\0\0\0\0\0\0\0\0\5\0\0\0@\0\0"...,
> 1843) = 1842
> read(8, "", 1) = 0
> close(8) = 0
> open("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", O_RDONLY|O_CLOEXEC) =
> 8
> fstat(8, {st_mode=S_IFREG|0644, st_size=741536, ...}) = 0
> ioctl(8, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS,
> 0x7ffe52ac0a90) = -1 ENOTTY (Inap
> fstat(8, {st_mode=S_IFREG|0644, st_size=741536, ...}) = 0
> lseek(8, 0, SEEK_CUR) = 0
> fcntl(8, F_DUPFD_CLOEXEC, 0) = 9
> fcntl(9, F_GETFL) = 0x8000 (flags O_RDONLY|O_LARGEFILE)
> fstat(9, {st_mode=S_IFREG|0644, st_size=741536, ...}) = 0
> mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
> 0x7f5403f06000
> lseek(9, 0, SEEK_CUR) = 0
> lseek(8, 0, SEEK_CUR) = 0
> lseek(9, 0, SEEK_SET) = 0
> fstat(9, {st_mode=S_IFREG|0644, st_size=741536, ...}) = 0
> lseek(9, 741376, SEEK_SET) = 741376
> read(9, "+\0++++++++++++++++++++++++++++++"..., 160) = 160
> lseek(9, 0, SEEK_SET) = 0
> lseek(9, 0, SEEK_SET) = 0
> lseek(9, 0, SEEK_SET) = 0
> read(9, "\0\1\0\0\0\23\1\0\0\4\0000FFTMh\275QN\0\0\1<\0\0\0\34GDEF"..., 4096)
> = 4096
> lseek(9, 4096, SEEK_SET) = 4096
> lseek(9, 4096, SEEK_SET) = 4096
> lseek(9, 4096, SEEK_SET) = 4096
> lseek(9, 4096, SEEK_SET) = 4096
> lseek(9, 4096, SEEK_SET) = 4096
> lseek(9, 4096, SEEK_SET) = 4096
> lseek(9, 4096, SEEK_SET) = 4096
> lseek(9, 4096, SEEK_SET) = 4096
> lseek(9, 4096, SEEK_SET) = 4096
> lseek(9, 4096, SEEK_SET) = 4096
> [...]
>
> Note that there are no other syscalls between the lseek() - Python simply
> seeks to the same position over and over again. I am not 100% sure that
> this is the cause of the slow-down, but it certainly looks like
> something is wrong here.
still nothing in the strace output is anything inside matplotlib: the
first line is a standard library module, and it's highly unlikely any
part of mpl is directly lseeking a font file (it's been dup()'ed).
Additionally, you're testing on python3, python3-matplotlib has only
been shipped from jessie onward, so your claim that upgrading from
jessie made its performance poor, it's impossible.
I'm afraid you will have to come up with something more related to mpl
that what's above, as it seems more a shot in the dark.
Regards,
--
Sandro Tosi (aka morph, morpheus, matrixhasu)
My website: http://matrixhasu.altervista.org/
Me at Debian: http://wiki.debian.org/SandroTosi
