i had to recently rewrite a mod_perl handler that was using Apache::CacheContent ( see: Apache::CacheContent and unforeseen side effects ).

now, i'm seeing way too much CPU utilization from the new Cache::FileCache-based handler. (at least, the bossman thinks it's too much load.)

with maybe a few requests/sec to this site, CPU is somewhere around 30% ... I've added PID logging in the handler to confirm that the CPU spikes are from this handler, and not from some other runaway process....

the output from top looks something like this: 

  PID USER     PRI  NI  SIZE  RSS SHARE STAT %CPU %MEM   TIME CPU COMM
+AND
 6199 nobody    15   0 14384  14M  5520 S    29.6  0.6   0:07   0 http
+d
 6251 nobody    15   0 14816  14M  5808 S    12.9  0.7   0:05   0 http
+d

[download]
and the PIDs are verified as part of the handler, and one step further, the spikes are from cache access, not from cache setting.

is there any way to lighten the CPU load?

and the relevant part of the handler ... 

 $did ||= 1100;
 my $cache = new Cache::FileCache ( 
                 { namespace => 'mySpace',
                   default_expires_in => '600', } );

 my $data = $cache->get( $did );
 warn "using data from cache! (PID: $$) " 
    if DEBUG and $data;

 if ( ! $data ) {
     use Net::SSLeay qw(get_https post_https sslcat make_headers make_
+form);
     my $url = "*****";

     $SIG{ALRM} = sub { return DECLINED; };
     alarm(15);
     my ($page, $response, %reply_headers) = 
          get_https($secureHost, 443, "$url");
     alarm(0);

     ### process $page to get $data .... 
     warn "setting cache now for $did (PID: $$) " if DEBUG;
     $cache->set( $did, $data, "600" );
   }

[download]

In reply to Cache::FileCache, CPU utilization, and bottlenecks .... by geektron

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