[PATCH v3 00/18] add "windowsize" (RFC 7440) support for tftp
Enrico Scholz
enrico.scholz at sigma-chemnitz.de
Mon Aug 15 01:42:04 PDT 2022
The tftp "windowsize" greatly improves the performance of tftp
transfers. This patchset adds support for it.
The first two patches are a little bit unrelated and enhance the 'cp
-v' output by giving information about the transfer speed. They can
be dropped if they are unwanted.
I tested the function with an iMX8MP platform in three environments:
- at home over OpenVPN on an ADSL 50 line --> 27x speedup
- 1 Gb/s connection --> 9x speedup
- connection over 100 Mb/s switch --> 4x speedup
In the test, I downloaded variable sized files which were filled from
/dev/urandom. E.g.
| :/ global tftp.windowsize=128
| :/ cp -v /mnt/tftp/data-100MiB /tmp/data && sha1sum /tmp/data
| [################################################################] 104857600 bytes, 98550375 bytes/s
For slow connection speeds, smaller files (1MiB, 4 MiB + 20 MiB) were
used.
The numbers (bytes/s) are
| windowsize | VPN | 1 Gb/s | 100 Mb/s |
|------------|-----------|------------|------------|
| 128 | 3.869.284 | 98.643.085 | 11.434.852 |
| 64 | 3.863.581 | 98.550.375 | 11.434.852 |
| 48 | 3.431.580 | 94.211.680 | 11.275.010 |
| 32 | 2.835.129 | 85.250.081 | 10.985.605 |
| 24 | 2.344.858 | 77.787.537 | 10.765.667 |
| 16 | 1.734.186 | 67.519.381 | 10.210.087 |
| 12 | 1.403.340 | 61.972.576 | 9.915.612 |
| 8 | 1.002.462 | 50.852.376 | 9.016.130 |
| 6 | 775.573 | 42.781.558 | 8.422.297 |
| 4 | 547.845 | 32.066.544 | 6.835.567 |
| 3 | 412.987 | 26.526.081 | 6.322.435 |
| 2 | 280.987 | 19.120.641 | 5.494.241 |
| 1 | 141.699 | 10.431.516 | 2.967.224 |
|------------|-----------|------------|------------|
| unpatched | 140.587 | 10.553.301 | 2.978.063 |
The window size related parts of the patchset (with deactivated
selftest) increase the barebox binary size by
| add/remove: 4/0 grow/shrink: 8/2 up/down: 1269/-32 (1237)
| Function old new delta
| tftp_handler 756 1200 +444
| tftp_put_data - 184 +184
| tftp_do_open 428 608 +180
| tftp_window_cache_remove - 124 +124
| tftp_window_cache_get_pos - 120 +120
| tftp_send 296 392 +96
| tftp_do_close 260 312 +52
| tftp_init 16 60 +44
| __FUNCTION__ 610 623 +13
| tftp_open 64 68 +4
| tftp_lookup 136 140 +4
| g_tftp_window_size - 4 +4
| tftp_read 180 164 -16
| tftp_poll 180 164 -16
| Total: Before=626114, After=627351, chg +0.20%
Turning of the datagram cache (CONFIG_FS_TFTP_REORDER_CACHE_SIZE=0)
reduces the overhead to
| add/remove: 1/0 grow/shrink: 7/2 up/down: 537/-32 (505)
| Function old new delta
| tftp_handler 756 992 +236
| tftp_do_open 428 564 +136
| tftp_send 296 392 +96
| tftp_init 16 60 +44
| __FUNCTION__ 610 623 +13
| tftp_open 64 68 +4
| tftp_lookup 136 140 +4
| g_tftp_window_size - 4 +4
| tftp_read 180 164 -16
| tftp_poll 180 164 -16
| Total: Before=626114, After=626619, chg +0.08%
Restoring the old behaviour by CONFIG_FS_TFTP_MAX_WINDOW_SIZE=1 shows
an overhead of
| add/remove: 1/0 grow/shrink: 7/2 up/down: 449/-32 (417)
| Function old new delta
| tftp_handler 756 988 +232
| tftp_do_open 428 564 +136
| tftp_init 16 60 +44
| __FUNCTION__ 610 623 +13
| tftp_send 296 308 +12
| tftp_open 64 68 +4
| tftp_lookup 136 140 +4
| g_tftp_window_size - 4 +4
| tftp_read 180 164 -16
| tftp_poll 180 164 -16
| Total: Before=626114, After=626531, chg +0.07%
---
v2 -> v3
- use "port=XX" mount options instead of global 'tftp.port' variable
- allocate fifo and send buffer dynamically based on block- and
window size of the transfer. Do not use fixed constants anymore
- rewritten cache code; use bitmap based functions with O(1)
complexity instead of iterating over (small) arrays
- unittest for cache functions
- add information about binary sizes
v1 -> v2
- fixes for non rfc7440 servers
---
Enrico Scholz (18):
progress: add close_progress() to display some statistics
libfile:copy_file: show statistics in verbose mode
tftp: add some 'const' annotations
tftp: allow to change tftp port
cmd:tftp: add '-P' option to set tftp server port number
tftp: minor refactoring of RRQ/WRQ packet generation code
tftp: replace hardcoded blksize by global constant
tftp: allocate buffers and fifo dynamically
tftp: add sanity check for OACK response
tftp: record whether tftp file is opened for lookup operation only
tftp: reduce block size on lookup requests
tftp: refactor data processing
tftp: detect out-of-memory situations
tftp: implement 'windowsize' (RFC 7440) support
tftp: do not use 'priv->block' for RRQ
tftp: add debug_assert() macro
tftp: reorder tftp packets
tftp: add selftest
commands/tftp.c | 22 +-
fs/Kconfig | 36 +++
fs/tftp-selftest.h | 56 ++++
fs/tftp.c | 640 +++++++++++++++++++++++++++++++++++++++-----
include/progress.h | 1 +
lib/libfile.c | 3 +
lib/show_progress.c | 25 ++
test/self/Kconfig | 7 +
8 files changed, 717 insertions(+), 73 deletions(-)
create mode 100644 fs/tftp-selftest.h
--
2.37.1
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