[Intel-gfx] [PATCH i-g-t 1/4] scripts/trace.pl: More hash key optimisations

[Tvrtko Ursulin]

On 20/01/2018 00:24, John.C.Harrison at Intel.com wrote:
> From: John Harrison <John.C.Harrison at Intel.com>
> 
> Cache the key count value rather than querying the hash every time.

This actually makes a difference? Just curious, I would have assumed 
Perl would know the size of it's arrays but maybe the implementation is 
stupid...

Btw I was using Devel::NTYProf in HTML output mode to profile my 
changes. It is quite easy to use and provided all the info I needed.

> Also assert that the database does not magically change size after the
> fixups.
> 
> Signed-off-by: John Harrison <John.C.Harrison at intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>   scripts/trace.pl | 9 ++++++---
>   1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/scripts/trace.pl b/scripts/trace.pl
> index cb93900d..7b8a920e 100755
> --- a/scripts/trace.pl
> +++ b/scripts/trace.pl
> @@ -508,7 +508,9 @@ foreach my $key (keys %db) {
>   }
>   
>   # Fix up incompletes
> -foreach my $key (keys %db) {
> +my @keys = keys(%db);

This array is unused except for the query below so I'd suggest to not 
have it.

> +my $keyCount = scalar(@keys);

About came case.. I won't complain too the max, since I'm happy you are 
finding the tool useful and improving it, but it would be good to stay 
within the same style of variable naming or we'll have a mish-mash of 
styles which won't help readability.

Regards,

Tvrtko

> +foreach my $key (@keys) {
>   	next unless exists $db{$key}->{'incomplete'};
>   
>   	# End the incomplete batch at the time next one starts
> @@ -522,7 +524,7 @@ foreach my $key (keys %db) {
>   		$next_key = db_key($ring, $ctx, $seqno + $i);
>   		$i++;
>   	} until ((exists $db{$next_key} and not exists $db{$next_key}->{'incomplete'})
> -		 or $i > scalar(keys(%db)));  # ugly stop hack
> +		 or $i > $keyCount);  # ugly stop hack
>   
>   	if (exists $db{$next_key}) {
>   		$db{$key}->{'notify'} = $db{$next_key}->{'end'};
> @@ -540,6 +542,7 @@ my $first_ts;
>   
>   my @sorted_keys = sort {$db{$a}->{'start'} <=> $db{$b}->{'start'}} keys %db;
>   my $re_sort = 0;
> +die "Database changed size?!" unless scalar(@sorted_keys) == $keyCount;
>   
>   foreach my $key (@sorted_keys) {
>   	my $ring = $db{$key}->{'ring'};
> @@ -565,7 +568,7 @@ foreach my $key (@sorted_keys) {
>   		do {
>   			$next_key = db_key($ring, $ctx, $seqno + $i);
>   			$i++;
> -		} until (exists $db{$next_key} or $i > scalar(keys(%db)));  # ugly stop hack
> +		} until (exists $db{$next_key} or $i > $keyCount);  # ugly stop hack
>   
>   		# 20us tolerance
>   		if (exists $db{$next_key} and $db{$next_key}->{'start'} < $start + 20) {
>