caiyu/nextpnr
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Add crude histogram feature, printed after placement and routing

Browse Source
This commit is contained in:
Eddie Hung 2018-08-03 23:39:42 -07:00
parent 85a436198c
commit be481cb130
3 changed files with 33 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
common/router1.cc
View File

@ -933,7 +933,7 @@ bool router1(Context *ctx, const Router1Cfg &cfg)
#ifndef NDEBUG
ctx->check();
#endif
timing_analysis(ctx, true /* print_path */);
timing_analysis(ctx, true /* slack_histogram */, true /* print_path */);
ctx->unlock();
return true;
} catch (log_execution_error_exception) {

34
common/timing.cc
View File

@ -27,6 +27,7 @@
NEXTPNR_NAMESPACE_BEGIN
typedef std::vector<const PortRef*> PortRefVector;
typedef std::map<delay_t, unsigned> DelayFrequency;
struct Timing
{
@ -35,8 +36,10 @@ struct Timing
delay_t min_slack;
PortRefVector current_path;
PortRefVector *crit_path;
DelayFrequency *slack_histogram;
Timing(Context *ctx, bool update, PortRefVector *crit_path = nullptr): ctx(ctx), update(update), min_slack(1.0e12 / ctx->target_freq), crit_path(crit_path) {}
Timing(Context *ctx, bool update, PortRefVector *crit_path = nullptr, DelayFrequency *slack_histogram = nullptr)
: ctx(ctx), update(update), min_slack(1.0e12 / ctx->target_freq), crit_path(crit_path), slack_histogram(slack_histogram) {}
delay_t follow_net(NetInfo *net, int path_length, delay_t slack)
{
@ -75,6 +78,8 @@ struct Timing
if (crit_path)
*crit_path = current_path;
}
if (slack_histogram)
(*slack_histogram)[slack]++;
} else {
// Default to the path ending here, if no further paths found
value = slack / path_length;
@ -178,11 +183,12 @@ void assign_budget(Context *ctx, bool quiet)
log_info("Checksum: 0x%08x\n", ctx->checksum());
}
void timing_analysis(Context *ctx, bool print_path)
void timing_analysis(Context *ctx, bool print_histogram, bool print_path)
{
PortRefVector crit_path;
DelayFrequency slack_histogram;
Timing timing(ctx, false /* update */, &crit_path);
Timing timing(ctx, false /* update */, print_path ? &crit_path : nullptr, print_histogram ? &slack_histogram : nullptr);
auto min_slack = timing.walk_paths();
if (print_path) {
@ -224,6 +230,28 @@ void timing_analysis(Context *ctx, bool print_path)
delay_t default_slack = delay_t(1.0e12 / ctx->target_freq);
log_info("estimated Fmax = %.2f MHz\n", 1e6 / (default_slack - min_slack));
if (print_histogram) {
constexpr unsigned num_bins = 20;
unsigned bar_width = 60;
auto min_slack = slack_histogram.begin()->first;
auto max_slack = slack_histogram.rbegin()->first;
auto bin_size = (max_slack - min_slack) / num_bins;
std::vector<unsigned> bins(num_bins+1);
unsigned max_freq = 0;
for (const auto& i : slack_histogram) {
auto& bin = bins[(i.first-min_slack) / bin_size];
bin += i.second;
max_freq = std::max(max_freq, bin);
}
bar_width = std::min(bar_width, max_freq);
log_break();
log_info("Slack histogram:\n");
log_info(" legend: * represents %d endpoint(s)\n", max_freq / bar_width);
for (unsigned i = 0; i < bins.size(); ++i)
log_info("%6d < ps < %6d |%s\n", min_slack + bin_size*i, min_slack + bin_size*(i+1), std::string(bins[i] * bar_width / max_freq, '*').c_str());
}
}
NEXTPNR_NAMESPACE_END

2
common/timing.h
View File

@ -29,7 +29,7 @@ void assign_budget(Context *ctx, bool quiet = false);
// Perform timing analysis and print out the fmax, and optionally the
// critical path
void timing_analysis(Context *ctx, bool print_path = false);
void timing_analysis(Context *ctx, bool slack_histogram = true, bool print_path = false);
NEXTPNR_NAMESPACE_END