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Add prevhash to template cache #58

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Merged
Sjors merged 1 commit into from
Nov 18, 2025
Merged

Add prevhash to template cache #58

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21 changes: 11 additions & 10 deletions src/sv2/template_provider.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -130,7 +130,7 @@ void Sv2TemplateProvider::Interrupt()
LOCK(m_tp_mutex);
try {
for (auto& t : GetBlockTemplates()) {
t.second->interruptWait();
t.second.second->interruptWait();
}
} catch (const ipc::Exception& e) {
// Bitcoin Core v30 does not yet implement interruptWait(), fall back
Expand Down Expand Up @@ -250,7 +250,6 @@ void Sv2TemplateProvider::ThreadSv2ClientHandler(size_t client_id)
{
try {
Timer timer(m_options.fee_check_interval);
std::shared_ptr<BlockTemplate> block_template;

const auto prepare_block_create_options = [this, client_id](node::BlockCreateOptions& options) -> bool {
{
Expand All @@ -265,6 +264,9 @@ void Sv2TemplateProvider::ThreadSv2ClientHandler(size_t client_id)
return true;
};

std::shared_ptr<BlockTemplate> block_template;
// Cache most recent block_template->getBlockHeader().hashPrevBlock result.
uint256 prev_hash;
while (!m_flag_interrupt_sv2) {
if (!block_template) {
LogPrintLevel(BCLog::SV2, BCLog::Level::Trace, "Generate initial block template for client id=%zu\n",
Expand All @@ -288,7 +290,7 @@ void Sv2TemplateProvider::ThreadSv2ClientHandler(size_t client_id)
LogPrintLevel(BCLog::SV2, BCLog::Level::Trace, "Assemble template: %.2fms\n",
Ticks<MillisecondsDouble>(SteadyClock::now() - time_start));

uint256 prev_hash{block_template->getBlockHeader().hashPrevBlock};
prev_hash = block_template->getBlockHeader().hashPrevBlock;
{
LOCK(m_tp_mutex);
if (prev_hash != m_best_prev_hash) {
Expand All @@ -299,7 +301,7 @@ void Sv2TemplateProvider::ThreadSv2ClientHandler(size_t client_id)

// Add template to cache before sending it, to prevent race
// condition: https://github.com/stratum-mining/stratum/issues/1773
m_block_template_cache.insert({template_id,block_template});
m_block_template_cache.insert({template_id,std::make_pair(prev_hash, block_template)});
}

{
Expand Down Expand Up @@ -346,7 +348,6 @@ void Sv2TemplateProvider::ThreadSv2ClientHandler(size_t client_id)
client_id);
}

uint256 old_prev_hash{block_template->getBlockHeader().hashPrevBlock};
std::shared_ptr<BlockTemplate> tmpl = block_template->waitNext(options);
// The client may have disconnected during the wait, check now to avoid
// a spurious IPC call and confusing log statements.
Expand All @@ -362,7 +363,7 @@ void Sv2TemplateProvider::ThreadSv2ClientHandler(size_t client_id)

{
LOCK(m_tp_mutex);
if (new_prev_hash != old_prev_hash) {
if (new_prev_hash != prev_hash) {
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@Sjors Sjors Nov 24, 2025

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Previously old_prev_hash probably should have been m_best_prev_hash.

LogPrintLevel(BCLog::SV2, BCLog::Level::Trace, "Tip changed, client id=%zu\n",
client_id);
future_template = true;
Expand All @@ -375,7 +376,7 @@ void Sv2TemplateProvider::ThreadSv2ClientHandler(size_t client_id)

// Add template to cache before sending it, to prevent race
// condition: https://github.com/stratum-mining/stratum/issues/1773
m_block_template_cache.insert({m_template_id,block_template});
m_block_template_cache.insert({m_template_id, std::make_pair(new_prev_hash,block_template)});
}

{
Expand Down Expand Up @@ -422,7 +423,7 @@ void Sv2TemplateProvider::RequestTransactionData(Sv2Client& client, node::Sv2Req

return;
}
block = (*cached_block->second).getBlock();
block = (*cached_block->second.second).getBlock();
}

{
Expand Down Expand Up @@ -497,7 +498,7 @@ void Sv2TemplateProvider::SubmitSolution(node::Sv2SubmitSolutionMsg solution)
* on the network. In case of a reorg the node will be able to switch
* faster because it already has (but not fully validated) the block.
*/
block_template = cached_block_template->second;
block_template = cached_block_template->second.second;
}

// Submit the solution to construct and process the block
Expand Down Expand Up @@ -555,7 +556,7 @@ void Sv2TemplateProvider::PruneBlockTemplateCache()
// If the blocks prevout is not the tip's prevout, delete it.
uint256 prev_hash = m_best_prev_hash;
std::erase_if(m_block_template_cache, [prev_hash] (const auto& kv) {
if (kv.second->getBlockHeader().hashPrevBlock != prev_hash) {
if (kv.second.first != prev_hash) {
return true;
}
return false;
Expand Down
5 changes: 3 additions & 2 deletions src/sv2/template_provider.h
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Original file line number Diff line number Diff line change
Expand Up @@ -104,9 +104,10 @@ class Sv2TemplateProvider : public Sv2EventsInterface
std::chrono::nanoseconds m_last_block_time GUARDED_BY(m_tp_mutex);

/**
* A cache that maps ids used in NewTemplate messages and its associated block template.
* A cache that maps ids used in NewTemplate messages and its associated
* <prevhash,block template>.
*/
using BlockTemplateCache = std::map<uint64_t, std::shared_ptr<BlockTemplate>>;
using BlockTemplateCache = std::map<uint64_t, std::pair<uint256, std::shared_ptr<BlockTemplate>>>;
BlockTemplateCache m_block_template_cache GUARDED_BY(m_tp_mutex);

public:
Expand Down
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