diff options
author | Matthew Jordan <mjordan@digium.com> | 2014-07-20 22:06:33 +0000 |
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committer | Matthew Jordan <mjordan@digium.com> | 2014-07-20 22:06:33 +0000 |
commit | a2c912e9972c91973ea66902d217746133f96026 (patch) | |
tree | 50e01d14ba62950e3f78766d5ba435ba51ca327d /channels/iax2/codec_pref.c | |
parent | b299052e203807c9a2111eb2cd919246d7589cb3 (diff) |
media formats: re-architect handling of media for performance improvements
In the old times media formats were represented using a bit field. This was
fast but had a few limitations.
1. Asterisk was limited in how many formats it could handle.
2. Formats, being a bit field, could not include any attribute information.
A format was strictly its type, e.g., "this is ulaw".
This was changed in Asterisk 10 (see
https://wiki.asterisk.org/wiki/display/AST/Media+Architecture+Proposal for
notes on that work) which led to the creation of the ast_format structure.
This structure allowed Asterisk to handle attributes and bundle information
with a format.
Additionally, ast_format_cap was created to act as a container for multiple
formats that, together, formed the capability of some entity. Another
mechanism was added to allow logic to be registered which performed format
attribute negotiation. Everywhere throughout the codebase Asterisk was
changed to use this strategy.
Unfortunately, in software, there is no free lunch. These new capabilities
came at a cost.
Performance analysis and profiling showed that we spend an inordinate
amount of time comparing, copying, and generally manipulating formats and
their related structures. Basic prototyping has shown that a reasonably
large performance improvement could be made in this area. This patch is the
result of that project, which overhauled the media format architecture
and its usage in Asterisk to improve performance.
Generally, the new philosophy for handling formats is as follows:
* The ast_format structure is reference counted. This removed a large amount
of the memory allocations and copying that was done in prior versions.
* In order to prevent race conditions while keeping things performant, the
ast_format structure is immutable by convention and lock-free. Violate this
tenet at your peril!
* Because formats are reference counted, codecs are also reference counted.
The Asterisk core generally provides built-in codecs and caches the
ast_format structures created to represent them. Generally, to prevent
inordinate amounts of module reference bumping, codecs and formats can be
added at run-time but cannot be removed.
* All compatibility with the bit field representation of codecs/formats has
been moved to a compatibility API. The primary user of this representation
is chan_iax2, which must continue to maintain its bit-field usage of formats
for interoperability concerns.
* When a format is negotiated with attributes, or when a format cannot be
represented by one of the cached formats, a new format object is created or
cloned from an existing format. That format may have the same codec
underlying it, but is a different format than a version of the format with
different attributes or without attributes.
* While formats are reference counted objects, the reference count maintained
on the format should be manipulated with care. Formats are generally cached
and will persist for the lifetime of Asterisk and do not explicitly need
to have their lifetime modified. An exception to this is when the user of a
format does not know where the format came from *and* the user may outlive
the provider of the format. This occurs, for example, when a format is read
from a channel: the channel may have a format with attributes (hence,
non-cached) and the user of the format may last longer than the channel (if
the reference to the channel is released prior to the format's reference).
For more information on this work, see the API design notes:
https://wiki.asterisk.org/wiki/display/AST/Media+Format+Rewrite
Finally, this work was the culmination of a large number of developer's
efforts. Extra thanks goes to Corey Farrell, who took on a large amount of the
work in the Asterisk core, chan_sip, and was an invaluable resource in peer
reviews throughout this project.
There were a substantial number of patches contributed during this work; the
following issues/patch names simply reflect some of the work (and will cause
the release scripts to give attribution to the individuals who work on them).
Reviews:
https://reviewboard.asterisk.org/r/3814
https://reviewboard.asterisk.org/r/3808
https://reviewboard.asterisk.org/r/3805
https://reviewboard.asterisk.org/r/3803
https://reviewboard.asterisk.org/r/3801
https://reviewboard.asterisk.org/r/3798
https://reviewboard.asterisk.org/r/3800
https://reviewboard.asterisk.org/r/3794
https://reviewboard.asterisk.org/r/3793
https://reviewboard.asterisk.org/r/3792
https://reviewboard.asterisk.org/r/3791
https://reviewboard.asterisk.org/r/3790
https://reviewboard.asterisk.org/r/3789
https://reviewboard.asterisk.org/r/3788
https://reviewboard.asterisk.org/r/3787
https://reviewboard.asterisk.org/r/3786
https://reviewboard.asterisk.org/r/3784
https://reviewboard.asterisk.org/r/3783
https://reviewboard.asterisk.org/r/3778
https://reviewboard.asterisk.org/r/3774
https://reviewboard.asterisk.org/r/3775
https://reviewboard.asterisk.org/r/3772
https://reviewboard.asterisk.org/r/3761
https://reviewboard.asterisk.org/r/3754
https://reviewboard.asterisk.org/r/3753
https://reviewboard.asterisk.org/r/3751
https://reviewboard.asterisk.org/r/3750
https://reviewboard.asterisk.org/r/3748
https://reviewboard.asterisk.org/r/3747
https://reviewboard.asterisk.org/r/3746
https://reviewboard.asterisk.org/r/3742
https://reviewboard.asterisk.org/r/3740
https://reviewboard.asterisk.org/r/3739
https://reviewboard.asterisk.org/r/3738
https://reviewboard.asterisk.org/r/3737
https://reviewboard.asterisk.org/r/3736
https://reviewboard.asterisk.org/r/3734
https://reviewboard.asterisk.org/r/3722
https://reviewboard.asterisk.org/r/3713
https://reviewboard.asterisk.org/r/3703
https://reviewboard.asterisk.org/r/3689
https://reviewboard.asterisk.org/r/3687
https://reviewboard.asterisk.org/r/3674
https://reviewboard.asterisk.org/r/3671
https://reviewboard.asterisk.org/r/3667
https://reviewboard.asterisk.org/r/3665
https://reviewboard.asterisk.org/r/3625
https://reviewboard.asterisk.org/r/3602
https://reviewboard.asterisk.org/r/3519
https://reviewboard.asterisk.org/r/3518
https://reviewboard.asterisk.org/r/3516
https://reviewboard.asterisk.org/r/3515
https://reviewboard.asterisk.org/r/3512
https://reviewboard.asterisk.org/r/3506
https://reviewboard.asterisk.org/r/3413
https://reviewboard.asterisk.org/r/3410
https://reviewboard.asterisk.org/r/3387
https://reviewboard.asterisk.org/r/3388
https://reviewboard.asterisk.org/r/3389
https://reviewboard.asterisk.org/r/3390
https://reviewboard.asterisk.org/r/3321
https://reviewboard.asterisk.org/r/3320
https://reviewboard.asterisk.org/r/3319
https://reviewboard.asterisk.org/r/3318
https://reviewboard.asterisk.org/r/3266
https://reviewboard.asterisk.org/r/3265
https://reviewboard.asterisk.org/r/3234
https://reviewboard.asterisk.org/r/3178
ASTERISK-23114 #close
Reported by: mjordan
media_formats_translation_core.diff uploaded by kharwell (License 6464)
rb3506.diff uploaded by mjordan (License 6283)
media_format_app_file.diff uploaded by kharwell (License 6464)
misc-2.diff uploaded by file (License 5000)
chan_mild-3.diff uploaded by file (License 5000)
chan_obscure.diff uploaded by file (License 5000)
jingle.diff uploaded by file (License 5000)
funcs.diff uploaded by file (License 5000)
formats.diff uploaded by file (License 5000)
core.diff uploaded by file (License 5000)
bridges.diff uploaded by file (License 5000)
mf-codecs-2.diff uploaded by file (License 5000)
mf-app_fax.diff uploaded by file (License 5000)
mf-apps-3.diff uploaded by file (License 5000)
media-formats-3.diff uploaded by file (License 5000)
ASTERISK-23715
rb3713.patch uploaded by coreyfarrell (License 5909)
rb3689.patch uploaded by mjordan (License 6283)
ASTERISK-23957
rb3722.patch uploaded by mjordan (License 6283)
mf-attributes-3.diff uploaded by file (License 5000)
ASTERISK-23958
Tested by: jrose
rb3822.patch uploaded by coreyfarrell (License 5909)
rb3800.patch uploaded by jrose (License 6182)
chan_sip.diff uploaded by mjordan (License 6283)
rb3747.patch uploaded by jrose (License 6182)
ASTERISK-23959 #close
Tested by: sgriepentrog, mjordan, coreyfarrell
sip_cleanup.diff uploaded by opticron (License 6273)
chan_sip_caps.diff uploaded by mjordan (License 6283)
rb3751.patch uploaded by coreyfarrell (License 5909)
chan_sip-3.diff uploaded by file (License 5000)
ASTERISK-23960 #close
Tested by: opticron
direct_media.diff uploaded by opticron (License 6273)
pjsip-direct-media.diff uploaded by file (License 5000)
format_cap_remove.diff uploaded by opticron (License 6273)
media_format_fixes.diff uploaded by opticron (License 6273)
chan_pjsip-2.diff uploaded by file (License 5000)
ASTERISK-23966 #close
Tested by: rmudgett
rb3803.patch uploaded by rmudgetti (License 5621)
chan_dahdi.diff uploaded by file (License 5000)
ASTERISK-24064 #close
Tested by: coreyfarrell, mjordan, opticron, file, rmudgett, sgriepentrog, jrose
rb3814.patch uploaded by rmudgett (License 5621)
moh_cleanup.diff uploaded by opticron (License 6273)
bridge_leak.diff uploaded by opticron (License 6273)
translate.diff uploaded by file (License 5000)
rb3795.patch uploaded by rmudgett (License 5621)
tls_fix.diff uploaded by mjordan (License 6283)
fax-mf-fix-2.diff uploaded by file (License 5000)
rtp_transfer_stuff uploaded by mjordan (License 6283)
rb3787.patch uploaded by rmudgett (License 5621)
media-formats-explicit-translate-format-3.diff uploaded by file (License 5000)
format_cache_case_fix.diff uploaded by opticron (License 6273)
rb3774.patch uploaded by rmudgett (License 5621)
rb3775.patch uploaded by rmudgett (License 5621)
rtp_engine_fix.diff uploaded by opticron (License 6273)
rtp_crash_fix.diff uploaded by opticron (License 6273)
rb3753.patch uploaded by mjordan (License 6283)
rb3750.patch uploaded by mjordan (License 6283)
rb3748.patch uploaded by rmudgett (License 5621)
media_format_fixes.diff uploaded by opticron (License 6273)
rb3740.patch uploaded by mjordan (License 6283)
rb3739.patch uploaded by mjordan (License 6283)
rb3734.patch uploaded by mjordan (License 6283)
rb3689.patch uploaded by mjordan (License 6283)
rb3674.patch uploaded by coreyfarrell (License 5909)
rb3671.patch uploaded by coreyfarrell (License 5909)
rb3667.patch uploaded by coreyfarrell (License 5909)
rb3665.patch uploaded by mjordan (License 6283)
rb3625.patch uploaded by coreyfarrell (License 5909)
rb3602.patch uploaded by coreyfarrell (License 5909)
format_compatibility-2.diff uploaded by file (License 5000)
core.diff uploaded by file (License 5000)
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@419044 65c4cc65-6c06-0410-ace0-fbb531ad65f3
Diffstat (limited to 'channels/iax2/codec_pref.c')
-rw-r--r-- | channels/iax2/codec_pref.c | 333 |
1 files changed, 333 insertions, 0 deletions
diff --git a/channels/iax2/codec_pref.c b/channels/iax2/codec_pref.c new file mode 100644 index 000000000..903dca4cc --- /dev/null +++ b/channels/iax2/codec_pref.c @@ -0,0 +1,333 @@ +/* + * Asterisk -- An open source telephony toolkit. + * + * Copyright (C) 2014, Digium, Inc. + * + * Joshua Colp <jcolp@digium.com> + * + * See http://www.asterisk.org for more information about + * the Asterisk project. Please do not directly contact + * any of the maintainers of this project for assistance; + * the project provides a web site, mailing lists and IRC + * channels for your use. + * + * This program is free software, distributed under the terms of + * the GNU General Public License Version 2. See the LICENSE file + * at the top of the source tree. + */ + +/*! \file + * + * \brief Media Format Bitfield Compatibility API + * + * \author Joshua Colp <jcolp@digium.com> + */ + +/*** MODULEINFO + <support_level>core</support_level> + ***/ + +#include "asterisk.h" + +ASTERISK_FILE_VERSION(__FILE__, "$Revision$") + +#include "asterisk/logger.h" +#include "asterisk/astobj2.h" +#include "asterisk/codec.h" +#include "asterisk/format.h" +#include "asterisk/format_compatibility.h" +#include "asterisk/format_cache.h" +#include "asterisk/format_cap.h" + +#include "include/codec_pref.h" +#include "include/format_compatibility.h" + +void iax2_codec_pref_convert(struct iax2_codec_pref *pref, char *buf, size_t size, int right) +{ + static int differential = (int) 'A'; + int x; + + if (right) { + for (x = 0; x < IAX2_CODEC_PREF_SIZE && x < size; x++) { + if (!pref->order[x]) { + break; + } + + buf[x] = pref->order[x] + differential; + } + + buf[x] = '\0'; + } else { + for (x = 0; x < IAX2_CODEC_PREF_SIZE && x < size; x++) { + if (buf[x] == '\0') { + break; + } + + pref->order[x] = buf[x] - differential; + } + + if (x < size) { + pref->order[x] = 0; + } + } +} + +struct ast_format *iax2_codec_pref_index(struct iax2_codec_pref *pref, int idx, struct ast_format **result) +{ + if ((idx >= 0) && (idx < sizeof(pref->order)) && pref->order[idx]) { + *result = ast_format_compatibility_bitfield2format(pref->order[idx]); + } else { + *result = NULL; + } + + return *result; +} + +void iax2_codec_pref_to_cap(struct iax2_codec_pref *pref, struct ast_format_cap *cap) +{ + int idx; + + for (idx = 0; idx < sizeof(pref->order); idx++) { + if (!pref->order[idx]) { + break; + } + ast_format_cap_append(cap, ast_format_compatibility_bitfield2format(pref->order[idx]), pref->framing[idx]); + } +} + +int iax2_codec_pref_string(struct iax2_codec_pref *pref, char *buf, size_t size) +{ + int x; + struct ast_format_cap *cap = ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT); + size_t total_len; + char *cur; + + if (!cap) { + return -1; + } + + /* This function is useless if you have less than a 6 character buffer. + * '(...)' is six characters. */ + if (size < 6) { + return -1; + } + + /* Convert the preferences into a format cap so that we can read the formst names */ + for (x = 0; x < IAX2_CODEC_PREF_SIZE; x++) { + uint64_t bitfield = iax2_codec_pref_order_value_to_format_bitfield(pref->order[x]); + if (!bitfield) { + break; + } + + iax2_format_compatibility_bitfield2cap(bitfield, cap); + } + + /* We know that at a minimum, 3 characters are used - (, ), and \0 */ + total_len = size - 3; + + memset(buf, 0, size); + + /* This character has already been accounted for total_len purposes */ + buf[0] = '('; + cur = buf + 1; + + /* Loop through the formats and write as many into the buffer as we can */ + for (x = 0; x < ast_format_cap_count(cap); x++) { + size_t name_len; + struct ast_format *fmt = ast_format_cap_get_format(cap, x); + const char *name = ast_format_get_name(fmt); + + name_len = strlen(name); + + /* all entries after the first need a delimiter character */ + if (x) { + name_len++; + } + + /* Terminate the list early if we don't have room for the entry. + * If it's not the last entry in the list, save enough room to write '...'. + */ + if (((x == ast_format_cap_count(cap) - 1) && (total_len < name_len)) || + ((x < ast_format_cap_count(cap) - 1) && (total_len < name_len + 3))) { + strcpy(cur, "..."); + cur += 3; + total_len -= 3; + ao2_ref(fmt, -1); + break; + } + + sprintf(cur, "%s%s", x ? "|" : "", name); + cur += name_len; + total_len -= name_len; + + ao2_ref(fmt, -1); + } + ao2_ref(cap, -1); + + /* These two characters have already been accounted for total_len purposes */ + cur[0] = ')'; + cur[1] = '\0'; + + return size - total_len; +} + +static void codec_pref_remove_index(struct iax2_codec_pref *pref, int codec_pref_index) +{ + int x; + + for (x = codec_pref_index; x < IAX2_CODEC_PREF_SIZE; x++) { + pref->order[x] = pref->order[x + 1]; + pref->framing[x] = pref->framing[x + 1]; + if (!pref->order[x]) { + return; + } + } +} + +/*! \brief Remove codec from pref list */ +static void codec_pref_remove(struct iax2_codec_pref *pref, int format_index) +{ + int x; + + if (!pref->order[0]) { + return; + } + + for (x = 0; x < IAX2_CODEC_PREF_SIZE; x++) { + if (!pref->order[x]) { + break; + } + + if (pref->order[x] == format_index) { + codec_pref_remove_index(pref, x); + break; + } + } +} + +void iax2_codec_pref_remove_missing(struct iax2_codec_pref *pref, uint64_t bitfield) +{ + int x; + + if (!pref->order[0]) { + return; + } + + for (x = 0; x < IAX2_CODEC_PREF_SIZE; x++) { + uint64_t format_as_bitfield = iax2_codec_pref_order_value_to_format_bitfield(pref->order[x]); + if (!pref->order[x]) { + break; + } + + /* If this format isn't in the bitfield, remove it from the prefs. */ + if (!(format_as_bitfield & bitfield)) { + codec_pref_remove_index(pref, x); + } + } +} + +uint64_t iax2_codec_pref_order_value_to_format_bitfield(uint64_t order_value) +{ + if (!order_value) { + return 0; + } + + return 1 << (order_value - 1); +} + +uint64_t iax2_codec_pref_format_bitfield_to_order_value(uint64_t bitfield) +{ + int format_index = 1; + + if (!bitfield) { + return 0; + } + + while (bitfield > 1) { + bitfield = bitfield >> 1; + format_index++; + } + + return format_index; +} + +/*! \brief Append codec to list */ +int iax2_codec_pref_append(struct iax2_codec_pref *pref, struct ast_format *format, unsigned int framing) +{ + uint64_t bitfield = ast_format_compatibility_format2bitfield(format); + int format_index = iax2_codec_pref_format_bitfield_to_order_value(bitfield); + int x; + + codec_pref_remove(pref, format_index); + + for (x = 0; x < IAX2_CODEC_PREF_SIZE; x++) { + if (!pref->order[x]) { + pref->order[x] = format_index; + pref->framing[x] = framing; + break; + } + } + + return x; +} + +/*! \brief Prepend codec to list */ +void iax2_codec_pref_prepend(struct iax2_codec_pref *pref, struct ast_format *format, unsigned int framing, + int only_if_existing) +{ + uint64_t bitfield = ast_format_compatibility_format2bitfield(format); + int x; + + /* Now find any existing occurrence, or the end */ + for (x = 0; x < IAX2_CODEC_PREF_SIZE; x++) { + if (!pref->order[x] || pref->order[x] == bitfield) + break; + } + + /* If we failed to find any occurrence, set to the end */ + if (x == IAX2_CODEC_PREF_SIZE) { + --x; + } + + if (only_if_existing && !pref->order[x]) { + return; + } + + /* Move down to make space to insert - either all the way to the end, + or as far as the existing location (which will be overwritten) */ + for (; x > 0; x--) { + pref->order[x] = pref->order[x - 1]; + pref->framing[x] = pref->framing[x - 1]; + } + + /* And insert the new entry */ + pref->order[0] = bitfield; + pref->framing[0] = framing; +} + +unsigned int iax2_codec_pref_getsize(struct iax2_codec_pref *pref, int idx) +{ + if ((idx >= 0) && (idx < sizeof(pref->order)) && pref->order[idx]) { + return pref->framing[idx]; + } else { + return 0; + } +} + +int iax2_codec_pref_setsize(struct iax2_codec_pref *pref, struct ast_format *format, int framems) +{ + int idx; + + for (idx = 0; idx < sizeof(pref->order); idx++) { + if (!pref->order[idx]) { + break; + } else if (ast_format_cmp(ast_format_compatibility_bitfield2format(pref->order[idx]), + format) != AST_FORMAT_CMP_EQUAL) { + continue; + } + pref->framing[idx] = framems; + return 0; + } + + return -1; +} |