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-rw-r--r--passes/memory/memory_bram.cc198
1 files changed, 156 insertions, 42 deletions
diff --git a/passes/memory/memory_bram.cc b/passes/memory/memory_bram.cc
index 83a1d5b1..86828989 100644
--- a/passes/memory/memory_bram.cc
+++ b/passes/memory/memory_bram.cc
@@ -63,6 +63,7 @@ struct rules_t
struct match_t {
IdString name;
dict<string, int> min_limits, max_limits;
+ bool or_next_if_better;
};
dict<IdString, bram_t> brams;
@@ -174,6 +175,7 @@ struct rules_t
match_t data;
data.name = RTLIL::escape_id(tokens[1]);
+ data.or_next_if_better = false;
while (next_line())
{
@@ -192,6 +194,11 @@ struct rules_t
continue;
}
+ if (GetSize(tokens) == 1 && tokens[0] == "or_next_if_better") {
+ data.or_next_if_better = true;
+ continue;
+ }
+
break;
}
@@ -217,7 +224,7 @@ struct rules_t
}
};
-bool replace_cell(Cell *cell, const rules_t::bram_t &bram, const rules_t::match_t&)
+bool replace_cell(Cell *cell, const rules_t::bram_t &bram, const rules_t::match_t &match, dict<string, int> &match_properties, int mode)
{
Module *module = cell->module;
@@ -247,7 +254,7 @@ bool replace_cell(Cell *cell, const rules_t::bram_t &bram, const rules_t::match_
transp_max = std::max(transp_max, pi.transp);
}
- log(" Mapping to bram type %s:\n", log_id(bram.name));
+ log(" Mapping to bram type %s:\n", log_id(bram.name));
int mem_size = cell->getParam("\\SIZE").as_int();
int mem_abits = cell->getParam("\\ABITS").as_int();
@@ -287,7 +294,7 @@ bool replace_cell(Cell *cell, const rules_t::bram_t &bram, const rules_t::match_
if (!clken)
clkdom = pair<SigBit, bool>(State::S1, false);
- log(" Write port #%d is in clock domain %s%s.\n",
+ log(" Write port #%d is in clock domain %s%s.\n",
cell_port_i, clkdom.second ? "" : "!",
clken ? log_signal(clkdom.first) : "~async~");
@@ -301,20 +308,20 @@ bool replace_cell(Cell *cell, const rules_t::bram_t &bram, const rules_t::match_
if (clken) {
if (pi.clocks == 0) {
- log(" Bram port %c%d has incompatible clock type.\n", pi.group + 'A', pi.index + 1);
+ log(" Bram port %c%d has incompatible clock type.\n", pi.group + 'A', pi.index + 1);
goto skip_bram_wport;
}
if (clock_domains.count(pi.clocks) && clock_domains.at(pi.clocks) != clkdom) {
- log(" Bram port %c%d is in a different clock domain.\n", pi.group + 'A', pi.index + 1);
+ log(" Bram port %c%d is in a different clock domain.\n", pi.group + 'A', pi.index + 1);
goto skip_bram_wport;
}
if (clock_polarities.count(pi.clkpol) && clock_polarities.at(pi.clkpol) != clkpol) {
- log(" Bram port %c%d has incompatible clock polarity.\n", pi.group + 'A', pi.index + 1);
+ log(" Bram port %c%d has incompatible clock polarity.\n", pi.group + 'A', pi.index + 1);
goto skip_bram_wport;
}
} else {
if (pi.clocks != 0) {
- log(" Bram port %c%d has incompatible clock type.\n", pi.group + 'A', pi.index + 1);
+ log(" Bram port %c%d has incompatible clock type.\n", pi.group + 'A', pi.index + 1);
goto skip_bram_wport;
}
}
@@ -327,12 +334,12 @@ bool replace_cell(Cell *cell, const rules_t::bram_t &bram, const rules_t::match_
sig_en.append(last_en_bit);
}
if (last_en_bit != wr_en[i + cell_port_i*mem_width]) {
- log(" Bram port %c%d has incompatible enable structure.\n", pi.group + 'A', pi.index + 1);
+ log(" Bram port %c%d has incompatible enable structure.\n", pi.group + 'A', pi.index + 1);
goto skip_bram_wport;
}
}
- log(" Mapped to bram port %c%d.\n", pi.group + 'A', pi.index + 1);
+ log(" Mapped to bram port %c%d.\n", pi.group + 'A', pi.index + 1);
pi.mapped_port = cell_port_i;
if (clken) {
@@ -350,7 +357,7 @@ bool replace_cell(Cell *cell, const rules_t::bram_t &bram, const rules_t::match_
goto mapped_wr_port;
}
- log(" Failed to map write port #%d.\n", cell_port_i);
+ log(" Failed to map write port #%d.\n", cell_port_i);
return false;
mapped_wr_port:;
}
@@ -405,7 +412,7 @@ grow_read_ports:;
if (!clken)
clkdom = pair<SigBit, bool>(State::S1, false);
- log(" Read port #%d is in clock domain %s%s.\n",
+ log(" Read port #%d is in clock domain %s%s.\n",
cell_port_i, clkdom.second ? "" : "!",
clken ? log_signal(clkdom.first) : "~async~");
@@ -419,29 +426,29 @@ grow_read_ports:;
if (clken) {
if (pi.clocks == 0) {
- log(" Bram port %c%d.%d has incompatible clock type.\n", pi.group + 'A', pi.index + 1, pi.dupidx + 1);
+ log(" Bram port %c%d.%d has incompatible clock type.\n", pi.group + 'A', pi.index + 1, pi.dupidx + 1);
goto skip_bram_rport;
}
if (clock_domains.count(pi.clocks) && clock_domains.at(pi.clocks) != clkdom) {
- log(" Bram port %c%d.%d is in a different clock domain.\n", pi.group + 'A', pi.index + 1, pi.dupidx + 1);
+ log(" Bram port %c%d.%d is in a different clock domain.\n", pi.group + 'A', pi.index + 1, pi.dupidx + 1);
goto skip_bram_rport;
}
if (clock_polarities.count(pi.clkpol) && clock_polarities.at(pi.clkpol) != clkpol) {
- log(" Bram port %c%d.%d has incompatible clock polarity.\n", pi.group + 'A', pi.index + 1, pi.dupidx + 1);
+ log(" Bram port %c%d.%d has incompatible clock polarity.\n", pi.group + 'A', pi.index + 1, pi.dupidx + 1);
goto skip_bram_rport;
}
if (read_transp.count(pi.transp) && read_transp.at(pi.transp) != transp) {
- log(" Bram port %c%d.%d has incompatible read transparancy.\n", pi.group + 'A', pi.index + 1, pi.dupidx + 1);
+ log(" Bram port %c%d.%d has incompatible read transparancy.\n", pi.group + 'A', pi.index + 1, pi.dupidx + 1);
goto skip_bram_rport;
}
} else {
if (pi.clocks != 0) {
- log(" Bram port %c%d.%d has incompatible clock type.\n", pi.group + 'A', pi.index + 1, pi.dupidx + 1);
+ log(" Bram port %c%d.%d has incompatible clock type.\n", pi.group + 'A', pi.index + 1, pi.dupidx + 1);
goto skip_bram_rport;
}
}
- log(" Mapped to bram port %c%d.%d.\n", pi.group + 'A', pi.index + 1, pi.dupidx + 1);
+ log(" Mapped to bram port %c%d.%d.\n", pi.group + 'A', pi.index + 1, pi.dupidx + 1);
pi.mapped_port = cell_port_i;
if (clken) {
@@ -463,15 +470,51 @@ grow_read_ports:;
goto mapped_rd_port;
}
- log(" Failed to map read port #%d.\n", cell_port_i);
+ log(" Failed to map read port #%d.\n", cell_port_i);
if (try_growing_more_read_ports) {
- log(" Growing more read ports by duplicating bram cells.\n");
+ log(" Growing more read ports by duplicating bram cells.\n");
goto grow_read_ports;
}
return false;
mapped_rd_port:;
}
+ if (mode <= 1)
+ {
+ match_properties["dups"] = dup_count;
+ match_properties["waste"] = match_properties["dups"] * match_properties["bwaste"];
+
+ int cells = ((match_properties["dbits"] + bram.dbits - 1) / bram.dbits) * ((match_properties["words"] + (1 << bram.abits) - 1) / (1 << bram.abits));
+ match_properties["efficiency"] = (100 * match_properties["bits"]) / (dup_count * cells * bram.dbits * (1 << bram.abits));
+
+ log(" Updated properties: dups=%d waste=%d efficiency=%d\n",
+ match_properties["dups"], match_properties["waste"], match_properties["efficiency"]);
+
+ for (auto it : match.min_limits) {
+ if (!match_properties.count(it.first))
+ log_error("Unknown property '%s' in match rule for bram type %s.\n",
+ it.first.c_str(), log_id(match.name));
+ if (match_properties[it.first] >= it.second)
+ continue;
+ log(" Rule for bram type %s rejected: requirement 'min %s %d' not met.\n",
+ log_id(match.name), it.first.c_str(), it.second);
+ return false;
+ }
+ for (auto it : match.max_limits) {
+ if (!match_properties.count(it.first))
+ log_error("Unknown property '%s' in match rule for bram type %s.\n",
+ it.first.c_str(), log_id(match.name));
+ if (match_properties[it.first] <= it.second)
+ continue;
+ log(" Rule for bram type %s rejected: requirement 'max %s %d' not met.\n",
+ log_id(match.name), it.first.c_str(), it.second);
+ return false;
+ }
+
+ if (mode == 1)
+ return true;
+ }
+
dict<SigSpec, pair<SigSpec, SigSpec>> dout_cache;
for (int grid_d = 0; grid_d*bram.dbits < mem_width; grid_d++)
@@ -479,7 +522,7 @@ grow_read_ports:;
for (int dupidx = 0; dupidx < dup_count; dupidx++)
{
Cell *c = module->addCell(module->uniquify(stringf("%s.%d.%d.%d", cell->name.c_str(), grid_d, grid_a, dupidx)), bram.name);
- log(" Creating %s cell at grid position <%d %d %d>: %s\n", log_id(bram.name), grid_d, grid_a, dupidx, log_id(c));
+ log(" Creating %s cell at grid position <%d %d %d>: %s\n", log_id(bram.name), grid_d, grid_a, dupidx, log_id(c));
for (auto &pi : portinfos)
{
@@ -585,6 +628,7 @@ void handle_cell(Cell *cell, const rules_t &rules)
log("\n");
pool<IdString> failed_brams;
+ dict<int, int> best_rule_cache;
for (int i = 0; i < GetSize(rules.matches); i++)
{
@@ -597,6 +641,23 @@ void handle_cell(Cell *cell, const rules_t &rules)
if (match.name.in(failed_brams))
continue;
+ int avail_rd_ports = 0;
+ int avail_wr_ports = 0;
+ for (int j = 0; j < bram.groups; j++) {
+ if (GetSize(bram.wrmode) < j || bram.wrmode.at(j) == 0)
+ avail_rd_ports += GetSize(bram.ports) < j ? bram.ports.at(j) : 0;
+ if (GetSize(bram.wrmode) < j || bram.wrmode.at(j) != 0)
+ avail_wr_ports += GetSize(bram.ports) < j ? bram.ports.at(j) : 0;
+ }
+
+ log(" Checking rule #%d for bram type %s:\n", i, log_id(match.name));
+ log(" Bram geometry: abits=%d dbits=%d wports=%d rports=%d\n", bram.abits, bram.dbits, avail_wr_ports, avail_rd_ports);
+
+ int dups = avail_rd_ports ? (match_properties["rports"] + avail_rd_ports - 1) / avail_rd_ports : 1;
+ match_properties["dups"] = dups;
+
+ log(" Estimated number of duplicates for more read ports: dups=%d\n", match_properties["dups"]);
+
int aover = match_properties["words"] % (1 << bram.abits);
int awaste = aover ? (1 << bram.abits) - aover : 0;
match_properties["awaste"] = awaste;
@@ -605,19 +666,28 @@ void handle_cell(Cell *cell, const rules_t &rules)
int dwaste = dover ? bram.dbits - dover : 0;
match_properties["dwaste"] = dwaste;
- int waste = awaste * bram.dbits + dwaste * (1 << bram.abits) - awaste * dwaste;
+ int bwaste = awaste * bram.dbits + dwaste * (1 << bram.abits) - awaste * dwaste;
+ match_properties["bwaste"] = bwaste;
+
+ int waste = match_properties["dups"] * bwaste;
match_properties["waste"] = waste;
- log(" Wasted bits for bram type %s: awaste=%d dwaste=%d waste=%d\n",
- log_id(match.name), awaste, dwaste, waste);
+ int cells = ((match_properties["dbits"] + bram.dbits - 1) / bram.dbits) * ((match_properties["words"] + (1 << bram.abits) - 1) / (1 << bram.abits));
+ int efficiency = (100 * match_properties["bits"]) / (dups * cells * bram.dbits * (1 << bram.abits));
+ match_properties["efficiency"] = efficiency;
+
+ log(" Metrics for %s: awaste=%d dwaste=%d bwaste=%d waste=%d efficiency=%d %d\n",
+ log_id(match.name), awaste, dwaste, bwaste, waste, efficiency, cells);
for (auto it : match.min_limits) {
+ if (it.first == "waste" || it.first == "dups")
+ continue;
if (!match_properties.count(it.first))
log_error("Unknown property '%s' in match rule for bram type %s.\n",
it.first.c_str(), log_id(match.name));
if (match_properties[it.first] >= it.second)
continue;
- log(" Rule #%d for bram type %s rejected: requirement 'min %s %d' not met.\n",
+ log(" Rule #%d for bram type %s rejected: requirement 'min %s %d' not met.\n",
i, log_id(match.name), it.first.c_str(), it.second);
goto next_match_rule;
}
@@ -627,21 +697,57 @@ void handle_cell(Cell *cell, const rules_t &rules)
it.first.c_str(), log_id(match.name));
if (match_properties[it.first] <= it.second)
continue;
- log(" Rule #%d for bram type %s rejected: requirement 'max %s %d' not met.\n",
+ log(" Rule #%d for bram type %s rejected: requirement 'max %s %d' not met.\n",
i, log_id(match.name), it.first.c_str(), it.second);
goto next_match_rule;
}
- log(" Rule #%d for bram type %s accepted.\n", i, log_id(match.name));
+ log(" Rule #%d for bram type %s accepted.\n", i, log_id(match.name));
+
+ if (match.or_next_if_better || !best_rule_cache.empty())
+ {
+ if (match.or_next_if_better && i+1 == GetSize(rules.matches))
+ log_error("Found 'or_next_if_better' in last match rule.\n");
+
+ if (!replace_cell(cell, bram, match, match_properties, 1)) {
+ log(" Mapping to bram type %s failed.\n", log_id(match.name));
+ failed_brams.insert(match.name);
+ goto next_match_rule;
+ }
+
+ log(" Storing for later selection.\n");
+ best_rule_cache[i] = match_properties["efficiency"];
+
+ if (match.or_next_if_better)
+ goto next_match_rule;
+
+ next_match_rule:
+ if (match.or_next_if_better || best_rule_cache.empty())
+ continue;
+
+ log(" Selecting best of %d rules:\n", GetSize(best_rule_cache));
+ int best_rule = best_rule_cache.begin()->first;
+
+ for (auto &it : best_rule_cache) {
+ if (it.second > best_rule_cache[best_rule])
+ best_rule = it.first;
+ log(" Efficiency for rule %d: %d\n", it.first, it.second);
+ }
+
+ log(" Selected rule %d with efficiency %d.\n", best_rule, best_rule_cache[best_rule]);
+ best_rule_cache.clear();
+
+ if (!replace_cell(cell, rules.brams.at(rules.matches.at(best_rule).name), rules.matches.at(best_rule), match_properties, 2))
+ log_error("Mapping to bram type %s after pre-selection failed.\n", log_id(rules.matches.at(best_rule).name));
+ return;
+ }
- if (!replace_cell(cell, bram, match)) {
- log(" Mapping to bram type %s failed.\n", log_id(match.name));
+ if (!replace_cell(cell, bram, match, match_properties, 0)) {
+ log(" Mapping to bram type %s failed.\n", log_id(match.name));
failed_brams.insert(match.name);
goto next_match_rule;
}
return;
-
- next_match_rule:;
}
log(" No acceptable bram resources found.\n");
@@ -663,7 +769,7 @@ struct MemoryBramPass : public Pass {
log("rules. A block ram description looks like this:\n");
log("\n");
log(" bram RAMB1024X32 # name of BRAM cell\n");
- log(" init 1 # set to '1' if BRAM can be initialized\n");
+ // log(" init 1 # set to '1' if BRAM can be initialized\n");
log(" abits 10 # number of address bits\n");
log(" dbits 32 # number of data bits\n");
log(" groups 2 # number of port groups\n");
@@ -690,27 +796,35 @@ struct MemoryBramPass : public Pass {
log("A match rule looks like this:\n");
log("\n");
log(" match RAMB1024X32\n");
- log(" max waste 16384 # only use this if <= 16384 bram bits are unused\n");
+ log(" max waste 16384 # only use this bram if <= 16k ram bits are unused\n");
+ log(" min efficiency 80 # only use this bram if efficiency is at least 80%%\n");
log(" endmatch\n");
log("\n");
log("It is possible to match against the following values with min/max rules:\n");
log("\n");
- log(" words .... number of words in memory in design\n");
- log(" abits .... number of adress bits on memory in design\n");
- log(" dbits .... number of data bits on memory in design\n");
- log(" wports ... number of write ports on memory in design\n");
- log(" rports ... number of read ports on memory in design\n");
- log(" ports .... number of ports on memory in design\n");
- log(" bits ..... number of bits in memory in design\n");
+ log(" words ........ number of words in memory in design\n");
+ log(" abits ........ number of adress bits on memory in design\n");
+ log(" dbits ........ number of data bits on memory in design\n");
+ log(" wports ....... number of write ports on memory in design\n");
+ log(" rports ....... number of read ports on memory in design\n");
+ log(" ports ........ number of ports on memory in design\n");
+ log(" bits ......... number of bits in memory in design\n");
+ log(" dups .......... number of duplications for more read ports\n");
log("\n");
- log(" awaste ... number of unused address slots for this match\n");
- log(" dwaste ... number of unused data bits for this match\n");
- log(" waste .... total number of unused bram bits for this match\n");
+ log(" awaste ....... number of unused address slots for this match\n");
+ log(" dwaste ....... number of unused data bits for this match\n");
+ log(" bwaste ....... number of unused bram bits for this match\n");
+ log(" waste ........ total number of unused bram bits (bwaste*dups)\n");
+ log(" efficiency ... total percentage of used and non-duplicated bits\n");
log("\n");
log("The interface for the created bram instances is dervived from the bram\n");
log("description. Use 'techmap' to convert the created bram instances into\n");
log("instances of the actual bram cells of your target architecture.\n");
log("\n");
+ log("A match containing the command 'or_next_if_better' is only used if it\n");
+ log("has a higher efficiency than the next match (and the one after that if\n");
+ log("the next also has 'or_next_if_better' set, and so forth).\n");
+ log("\n");
}
virtual void execute(vector<string> args, Design *design)
{
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-24 22:24:08 +0000