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Kernel: Reduce the number of E1000 register reads while receiving

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There is no need to read and write the receive tail pointer for every
packet. This change bumped my TCP speed from ~11MB/s to ~40MB/s which is
my network speed limit
This commit is contained in:
Bananymous
2026-06-28 22:13:53 +03:00
parent 8f4e15b78e
commit c0bd07174d
1 changed files with 12 additions and 5 deletions
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17
kernel/kernel/Networking/E1000/E1000.cpp
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@@ -319,14 +319,16 @@ namespace Kernel
void E1000::receive_thread() void E1000::receive_thread()
{ {
SpinLockGuard _(m_rx_lock); SpinLockGuard guard(m_rx_lock);
uint32_t rx_current = 0;
while (!m_thread_should_die) while (!m_thread_should_die)
{ {
uint32_t rx_tail = rx_current;
for (;;) for (;;)
{ {
const uint32_t rx_current = (read32(REG_RDT0) + 1) % E1000_RX_DESCRIPTOR_COUNT;
auto& descriptor = reinterpret_cast<volatile e1000_rx_desc*>(m_rx_descriptor_region->vaddr())[rx_current]; auto& descriptor = reinterpret_cast<volatile e1000_rx_desc*>(m_rx_descriptor_region->vaddr())[rx_current];
if (!(descriptor.status & 1)) if (!(descriptor.status & 1))
break; break;
@@ -344,10 +346,15 @@ namespace Kernel
m_rx_lock.lock(); m_rx_lock.lock();
descriptor.status = 0; descriptor.status = 0;
write32(REG_RDT0, rx_current);
rx_tail = rx_current;
rx_current = (rx_current + 1) % E1000_RX_DESCRIPTOR_COUNT;
} }
SpinLockAsMutex smutex(m_rx_lock, InterruptState::Enabled); if (rx_current != rx_tail)
write32(REG_RDT0, rx_tail);
SpinLockGuardAsMutex smutex(guard);
m_rx_blocker.block_indefinite(&smutex); m_rx_blocker.block_indefinite(&smutex);
} }