Mercurial > hg > nginx
view src/event/quic/bpf/bpfgen.sh @ 8946:56dec0d4e5b1 quic
QUIC: avoid excessive buffer allocations in stream output.
Previously, when a few bytes were send to a QUIC stream by the application, a
4K buffer was allocated for these bytes. Then a STREAM frame was created and
that entire buffer was used as data for that frame. The frame with the buffer
were in use up until the frame was acked by client. Meanwhile, when more
bytes were send to the stream, more buffers were allocated and assigned as
data to newer STREAM frames. In this scenario most buffer memory is unused.
Now the unused part of the stream output buffer is available for further
stream output while earlier parts of the buffer are waiting to be acked.
This is achieved by splitting the output buffer.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Fri, 24 Dec 2021 18:13:51 +0300 |
parents | 7df607cb2d11 |
children |
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#!/bin/bash export LANG=C set -e if [ $# -lt 1 ]; then echo "Usage: PROGNAME=foo LICENSE=bar $0 <bpf object file>" exit 1 fi self=$0 filename=$1 funcname=$PROGNAME generate_head() { cat << END /* AUTO-GENERATED, DO NOT EDIT. */ #include <stddef.h> #include <stdint.h> #include "ngx_bpf.h" END } generate_tail() { cat << END ngx_bpf_program_t $PROGNAME = { .relocs = bpf_reloc_prog_$funcname, .nrelocs = sizeof(bpf_reloc_prog_$funcname) / sizeof(bpf_reloc_prog_$funcname[0]), .ins = bpf_insn_prog_$funcname, .nins = sizeof(bpf_insn_prog_$funcname) / sizeof(bpf_insn_prog_$funcname[0]), .license = "$LICENSE", .type = BPF_PROG_TYPE_SK_REUSEPORT, }; END } process_relocations() { echo "static ngx_bpf_reloc_t bpf_reloc_prog_$funcname[] = {" objdump -r $filename | awk '{ if (enabled && $NF > 0) { off = strtonum(sprintf("0x%s", $1)); name = $3; printf(" { \"%s\", %d },\n", name, off/8); } if ($1 == "OFFSET") { enabled=1; } }' echo "};" echo } process_section() { echo "static struct bpf_insn bpf_insn_prog_$funcname[] = {" echo " /* opcode dst src offset imm */" section_info=$(objdump -h $filename --section=$funcname | grep "1 $funcname") # dd doesn't know hex length=$(printf "%d" 0x$(echo $section_info | cut -d ' ' -f3)) offset=$(printf "%d" 0x$(echo $section_info | cut -d ' ' -f6)) for ins in $(dd if="$filename" bs=1 count=$length skip=$offset status=none | xxd -p -c 8) do opcode=0x${ins:0:2} srcdst=0x${ins:2:2} # bytes are dumped in LE order offset=0x${ins:6:2}${ins:4:2} # short immedi=0x${ins:14:2}${ins:12:2}${ins:10:2}${ins:8:2} # int dst="$(($srcdst & 0xF))" src="$(($srcdst & 0xF0))" src="$(($src >> 4))" opcode=$(printf "0x%x" $opcode) dst=$(printf "BPF_REG_%d" $dst) src=$(printf "BPF_REG_%d" $src) offset=$(printf "%d" $offset) immedi=$(printf "0x%x" $immedi) printf " { %4s, %11s, %11s, (int16_t) %6s, %10s },\n" $opcode $dst $src $offset $immedi done cat << END }; END } generate_head process_relocations process_section generate_tail