Tame BBRv3 Max feedback loop

This commit is contained in:
byjoey
2026-06-15 18:13:27 +08:00
parent a177824bcf
commit 5d3245018f
3 changed files with 28 additions and 141 deletions
+1 -1
View File
@@ -122,7 +122,7 @@ x86_64-7.0.11-max
arm64-7.0.11-max
```
其中不带 `-max` 的 tag 是标准 BBRv3 内核,带 `-max` 的 tag 是 BBRv3 Max 极限内核。Max 版会弱化/关闭 BBRv3 的降速、ECN、loss/inflight 收敛等控制路径,只适合自有链路极限测速挑战,不建议日常生产使用。
其中不带 `-max` 的 tag 是标准 BBRv3 内核,带 `-max` 的 tag 是 BBRv3 Max 极限内核。Max 版会极度弱化 BBRv3 的降速、ECN、loss/inflight 收敛力度,但保留反馈闭环,只适合自有链路极限测速挑战,不建议日常生产使用。
## 检查 BBRv3 状态
+1 -1
View File
@@ -1004,7 +1004,7 @@ select_kernel_profile() {
;;
2)
KERNEL_PROFILE="max"
echo -e "\033[31m警告:BBR v3 Max 会弱化/关闭降速与惩罚逻辑,只适合极限测速挑战,不建议日常生产使用。\033[0m"
echo -e "\033[31m警告:BBR v3 Max 会极度弱化降速与惩罚逻辑但保留反馈闭环,只适合极限测速挑战,不建议日常生产使用。\033[0m"
;;
*)
echo -e "\033[31m输入无效,取消安装。\033[0m"
+26 -139
View File
@@ -22,38 +22,38 @@ path = Path(sys.argv[1])
text = path.read_text()
replacements = {
r"static const u32 bbr_probe_rtt_win_ms = .*?;": "static const u32 bbr_probe_rtt_win_ms = 60 * 60 * 1000;",
r"static const u32 bbr_probe_rtt_cwnd_gain = .*?;": "static const u32 bbr_probe_rtt_cwnd_gain = BBR_UNIT * 3;",
r"static const u32 bbr_probe_rtt_mode_ms = .*?;": "static const u32 bbr_probe_rtt_mode_ms = 0;",
r"static const u32 bbr_probe_rtt_win_ms = .*?;": "static const u32 bbr_probe_rtt_win_ms = 10000;",
r"static const u32 bbr_probe_rtt_cwnd_gain = .*?;": "static const u32 bbr_probe_rtt_cwnd_gain = BBR_UNIT * 2;",
r"static const u32 bbr_probe_rtt_mode_ms = .*?;": "static const u32 bbr_probe_rtt_mode_ms = 10;",
r"static const u32 bbr_tso_rtt_shift = .*?;": "static const u32 bbr_tso_rtt_shift = 2;",
r"static const int bbr_pacing_margin_percent = .*?;": "static const int bbr_pacing_margin_percent = 0;",
r"static const int bbr_startup_pacing_gain = .*?;": "static const int bbr_startup_pacing_gain = BBR_UNIT * 15 / 4;",
r"static const int bbr_startup_cwnd_gain = .*?;": "static const int bbr_startup_cwnd_gain = BBR_UNIT * 15 / 4;",
r"static const int bbr_drain_gain = .*?;": "static const int bbr_drain_gain = BBR_UNIT;",
r"static const int bbr_cwnd_gain = .*?;": "static const int bbr_cwnd_gain = BBR_UNIT * 15 / 4;",
r"static const int bbr_startup_pacing_gain = .*?;": "static const int bbr_startup_pacing_gain = BBR_UNIT * 4;",
r"static const int bbr_startup_cwnd_gain = .*?;": "static const int bbr_startup_cwnd_gain = BBR_UNIT * 4;",
r"static const int bbr_drain_gain = .*?;": "static const int bbr_drain_gain = BBR_UNIT / 2;",
r"static const int bbr_cwnd_gain = .*?;": "static const int bbr_cwnd_gain = BBR_UNIT * 4;",
r"static const u32 bbr_cwnd_min_target = .*?;": "static const u32 bbr_cwnd_min_target = 64;",
r"static const u32 bbr_full_bw_thresh = .*?;": "static const u32 bbr_full_bw_thresh = BBR_UNIT * 101 / 100;",
r"static const u32 bbr_full_bw_cnt = .*?;": "static const u32 bbr_full_bw_cnt = 12;",
r"static const u32 bbr_full_bw_cnt = .*?;": "static const u32 bbr_full_bw_cnt = 16;",
r"static const int bbr_extra_acked_gain = .*?;": "static const int bbr_extra_acked_gain = BBR_UNIT * 4;",
r"static const u32 bbr_extra_acked_max_us = .*?;": "static const u32 bbr_extra_acked_max_us = 1000 * 1000;",
r"static const bool bbr_precise_ece_ack = .*?;": "static const bool bbr_precise_ece_ack = false;",
r"static const u32 bbr_extra_acked_max_us = .*?;": "static const u32 bbr_extra_acked_max_us = 750 * 1000;",
r"static const bool bbr_precise_ece_ack = .*?;": "static const bool bbr_precise_ece_ack = true;",
r"static const u32 bbr_ecn_max_rtt_us = .*?;": "static const u32 bbr_ecn_max_rtt_us = 0;",
r"static const u32 bbr_beta = .*?;": "static const u32 bbr_beta = 0;",
r"static const u32 bbr_ecn_alpha_gain = .*?;": "static const u32 bbr_ecn_alpha_gain = 0;",
r"static const u32 bbr_ecn_alpha_init = .*?;": "static const u32 bbr_ecn_alpha_init = 0;",
r"static const u32 bbr_ecn_factor = .*?;": "static const u32 bbr_ecn_factor = 0;",
r"static const u32 bbr_ecn_thresh = .*?;": "static const u32 bbr_ecn_thresh = 0;",
r"static const u32 bbr_ecn_reprobe_gain = .*?;": "static const u32 bbr_ecn_reprobe_gain = 0;",
r"static const u32 bbr_loss_thresh = [^\n]*": "static const u32 bbr_loss_thresh = BBR_UNIT; /* max: effectively disabled */",
r"static const bool bbr_loss_probe_recovery = .*?;": "static const bool bbr_loss_probe_recovery = false;",
r"static const u32 bbr_full_loss_cnt = .*?;": "static const u32 bbr_full_loss_cnt = 0;",
r"static const u32 bbr_full_ecn_cnt = .*?;": "static const u32 bbr_full_ecn_cnt = 0;",
r"static const u32 bbr_inflight_headroom = .*?;": "static const u32 bbr_inflight_headroom = 0;",
r"static const u32 bbr_beta = .*?;": "static const u32 bbr_beta = BBR_UNIT * 5 / 100;",
r"static const u32 bbr_ecn_alpha_gain = .*?;": "static const u32 bbr_ecn_alpha_gain = BBR_UNIT * 1 / 64;",
r"static const u32 bbr_ecn_alpha_init = .*?;": "static const u32 bbr_ecn_alpha_init = BBR_UNIT * 1 / 4;",
r"static const u32 bbr_ecn_factor = .*?;": "static const u32 bbr_ecn_factor = BBR_UNIT * 5 / 100;",
r"static const u32 bbr_ecn_thresh = .*?;": "static const u32 bbr_ecn_thresh = BBR_UNIT * 9 / 10;",
r"static const u32 bbr_ecn_reprobe_gain = .*?;": "static const u32 bbr_ecn_reprobe_gain = BBR_UNIT;",
r"static const u32 bbr_loss_thresh = [^\n]*": "static const u32 bbr_loss_thresh = BBR_UNIT * 10 / 100; /* max: tolerate 10% loss before backing off */",
r"static const bool bbr_loss_probe_recovery = .*?;": "static const bool bbr_loss_probe_recovery = true;",
r"static const u32 bbr_full_loss_cnt = .*?;": "static const u32 bbr_full_loss_cnt = 24;",
r"static const u32 bbr_full_ecn_cnt = .*?;": "static const u32 bbr_full_ecn_cnt = 8;",
r"static const u32 bbr_inflight_headroom = .*?;": "static const u32 bbr_inflight_headroom = BBR_UNIT * 1 / 100;",
r"static const u32 bbr_bw_probe_cwnd_gain = .*?;": "static const u32 bbr_bw_probe_cwnd_gain = 3;",
r"static const u32 bbr_bw_probe_max_rounds = .*?;": "static const u32 bbr_bw_probe_max_rounds = 1;",
r"static const u32 bbr_bw_probe_max_rounds = .*?;": "static const u32 bbr_bw_probe_max_rounds = 4;",
r"static const u32 bbr_bw_probe_rand_rounds = .*?;": "static const u32 bbr_bw_probe_rand_rounds = 1;",
r"static const u32 bbr_bw_probe_base_us = .*?;": "static const u32 bbr_bw_probe_base_us = 1000;",
r"static const u32 bbr_bw_probe_rand_us = .*?;": "static const u32 bbr_bw_probe_rand_us = 1;",
r"static const u32 bbr_bw_probe_base_us = .*?;": "static const u32 bbr_bw_probe_base_us = 100 * 1000;",
r"static const u32 bbr_bw_probe_rand_us = .*?;": "static const u32 bbr_bw_probe_rand_us = 50 * 1000;",
}
missing = []
@@ -62,101 +62,6 @@ for pattern, replacement in replacements.items():
if count != 1:
missing.append(pattern)
def find_matching(source, open_pos, open_char, close_char):
depth = 0
i = open_pos
in_string = None
in_line_comment = False
in_block_comment = False
escaped = False
while i < len(source):
ch = source[i]
nxt = source[i + 1] if i + 1 < len(source) else ""
if in_line_comment:
if ch == "\n":
in_line_comment = False
i += 1
continue
if in_block_comment:
if ch == "*" and nxt == "/":
in_block_comment = False
i += 2
continue
i += 1
continue
if in_string:
if escaped:
escaped = False
elif ch == "\\":
escaped = True
elif ch == in_string:
in_string = None
i += 1
continue
if ch == "/" and nxt == "/":
in_line_comment = True
i += 2
continue
if ch == "/" and nxt == "*":
in_block_comment = True
i += 2
continue
if ch in ('"', "'"):
in_string = ch
i += 1
continue
if ch == open_char:
depth += 1
elif ch == close_char:
depth -= 1
if depth == 0:
return i
i += 1
return -1
def next_code_char(source, pos):
i = pos
while i < len(source):
if source[i].isspace():
i += 1
continue
if source.startswith("//", i):
j = source.find("\n", i + 2)
i = len(source) if j == -1 else j + 1
continue
if source.startswith("/*", i):
j = source.find("*/", i + 2)
i = len(source) if j == -1 else j + 2
continue
return i
return -1
def replace_function_body(source, name, body):
for match in re.finditer(rf"\b{re.escape(name)}\s*\(", source):
open_paren = source.find("(", match.start())
close_paren = find_matching(source, open_paren, "(", ")")
if close_paren == -1:
continue
code_pos = next_code_char(source, close_paren + 1)
if code_pos == -1:
continue
if source[code_pos] == ";":
continue
if source[code_pos] != "{":
continue
close_brace = find_matching(source, code_pos, "{", "}")
if close_brace == -1:
continue
return source[:code_pos + 1] + body + source[close_brace:]
missing.append(f"function {name}")
return source
pacing_pattern = re.compile(
r"static const int bbr_pacing_gain\[\] = \{\n"
r".*?\n"
@@ -164,8 +69,8 @@ pacing_pattern = re.compile(
re.S,
)
pacing_replacement = """static const int bbr_pacing_gain[] = {
\tBBR_UNIT * 15 / 4,\t/* UP: max-rate probe */
\tBBR_UNIT,\t\t/* DOWN: no intentional drain */
\tBBR_UNIT * 7 / 2,\t/* UP: extreme but still feedback-bound */
\tBBR_UNIT / 2,\t\t/* DOWN: preserve a minimal drain phase */
\tBBR_UNIT * 5 / 4,\t/* CRUISE: keep pressure on the pipe */
\tBBR_UNIT * 2,\t\t/* REFILL: refill aggressively */
};"""
@@ -173,24 +78,6 @@ text, pacing_count = pacing_pattern.subn(pacing_replacement, text, count=1)
if pacing_count != 1:
missing.append("static const int bbr_pacing_gain[]")
extreme_bodies = {
"bbr_bw": "\n\treturn bbr_max_bw(sk);\n",
"bbr_can_use_ecn": "\n\treturn false;\n",
"bbr_check_ecn_too_high_in_startup": "\n\treturn;\n",
"bbr_update_ecn_alpha": "\n\treturn -1;\n",
"bbr_plb": "\n\treturn;\n",
"bbr_handle_queue_too_high_in_startup": "\n\treturn;\n",
"bbr_is_inflight_too_high": "\n\treturn false;\n",
"bbr_handle_inflight_too_high": "\n\treturn;\n",
"bbr_bound_cwnd_for_inflight_model": "\n\treturn;\n",
"bbr_adapt_lower_bounds": "\n\treturn;\n",
"bbr_check_loss_too_high_in_startup": "\n\treturn;\n",
"bbr_check_drain": "\n\treturn;\n",
}
for function_name, body in extreme_bodies.items():
text = replace_function_body(text, function_name, body)
if missing:
print("Failed to apply BBRv3 max profile; missing patterns:", file=sys.stderr)
for item in missing: