disk io works using cache - also pid cache cleanup and pid cache dump

bindings/SigarWrapper.pm

@@ -43,6 +43,7 @@ my %has_name_arg = map { $_, 1 } qw(FileSystemUsage DiskUsage
                                     FileAttrs DirStat DirUsage
                                     NetInterfaceConfig NetInterfaceStat);
 
+
 my %proc_no_arg = map { $_, 1 } qw(stat);
 
 my %get_not_impl = map { $_, 1 } qw(net_address net_route net_connection net_stat cpu_perc
@@ -527,6 +528,7 @@ use vars qw(%classes %cmds);
          plat => '*'
       },
     ],
+
     ProcMem => [
       {
          name => 'size', type => 'Long',
@@ -641,9 +643,37 @@ use vars qw(%classes %cmds);
       {
          name => 'bytes_total', type => 'Long',
          desc => 'Bytes Total',
-         plat => 'LW'
+         plat => 'LWAHS'
       }
     ],
+
+    ProcCumulativeDiskIO => [
+      {
+         name => 'bytes_read', type => 'Long',
+         desc => 'Bytes Read from Start',
+         plat => 'LW'
+      },
+      {
+         name => 'bytes_written', type => 'Long',
+         desc => 'Bytes Written from Start',
+         plat => 'LW'
+      },
+      {
+         name => 'bytes_total', type => 'Long',
+         desc => 'Bytes Total from Start',
+         plat => 'LWAHS'
+      }
+    ],
+
+    DumpPidCache => [
+      {
+         name => 'dummy', type => 'Long',
+         desc => 'Dummy',
+         plat => 'LWAHS'
+      }
+    ],
+
+
     ProcState => [
       {
          name => 'state', type => 'Char',

bindings/java/src/org/hyperic/sigar/Sigar.java

@@ -42,6 +42,8 @@ public class Sigar implements SigarProxy {
     private static String loadError = null;
 
     public static final long FIELD_NOTIMPL = -1;
+    public static final int PID_PROC_CPU_CACHE = 1;
+    public static final int PID_PROC_IO_CACHE = 2;
 
     /**
      * The Sigar java version.
@@ -661,6 +663,34 @@ public class Sigar implements SigarProxy {
     	return getProcDiskIO(convertPid(pid));
     }
 
+   /**
+     * Get process cumulative disk IO info.
+     * @param pid THe process id.
+     * @exception SigarException on failure.
+     */
+    public ProcCumulativeDiskIO getProcCumulativeDiskIO(long pid) throws SigarException {
+        try {
+                return ProcCumulativeDiskIO.fetch(this, pid);
+        } catch (UnsatisfiedLinkError linkErrorException) {
+                // We want to handle exceptions gracefully even if the linked
+                // shared library is older and isn't compiled with the ProcDiskIO APIs.
+                // The downside of this is that we throw SigarNotImplemented exception
+                // also when the shared library can't be loaded.
+                SigarException sigarException = new SigarNotImplementedException();
+                sigarException.initCause(linkErrorException);
+                throw sigarException;
+        }
+    }
+
+  public ProcCumulativeDiskIO getProcCumulativeDiskIO(String pid) throws SigarException {
+        return getProcCumulativeDiskIO(convertPid(pid));
+  }
+
+  public DumpPidCache dumpPidCache() throws SigarException {
+       return DumpPidCache.fetch(this);
+  }
+
+
     /**
      * Get the cumulative cpu time for the calling thread.
      */

bindings/java/src/org/hyperic/sigar/SigarProxy.java

@@ -110,6 +110,12 @@ public interface SigarProxy {
 
     public ProcDiskIO getProcDiskIO(String pid) throws SigarException;
 
+    public ProcCumulativeDiskIO getProcCumulativeDiskIO(long pid) throws SigarException;
+
+    public ProcCumulativeDiskIO getProcCumulativeDiskIO(String pid) throws SigarException;
+
+    public DumpPidCache dumpPidCache() throws SigarException;
+
     public FileSystem[] getFileSystemList() throws SigarException;
 
     public FileSystemMap getFileSystemMap() throws SigarException;

bindings/java/src/org/hyperic/sigar/cmd/PidCacheInfo.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2006-2007 Hyperic, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.hyperic.sigar.cmd;
+
+import org.hyperic.sigar.SigarException;
+import org.hyperic.sigar.SigarPermissionDeniedException;
+
+/**
+ * Display all pid cache information.
+ */
+public class PidCacheInfo extends SigarCommandBase {
+
+
+    public PidCacheInfo(Shell shell) {
+        super(shell);
+    }
+
+    public PidCacheInfo() {
+        super();
+    }
+
+    protected boolean validateArgs(String[] args) {
+        return true;
+    }
+
+    public String getUsageShort() {
+        return "Display cache info for CPU cache and for IO cache";
+    }
+
+    public boolean isPidCompleter() {
+        return false;
+    }
+
+    public void output(String[] args) throws SigarException {
+        sigar.dumpPidCache();
+    }
+}

bindings/java/src/org/hyperic/sigar/cmd/ProcInfo.java

@@ -103,6 +103,11 @@ public class ProcInfo extends SigarCommandBase {
         try {
         	println("diskio=" + sigar.getProcDiskIO(pid));
         } catch (SigarException e) {}
+
+ 	try {
+                println("cumulative diskio=" + sigar.getProcCumulativeDiskIO(pid));
+        } catch (SigarException e) {}
+
     }
 
     public static void main(String[] args) throws Exception {

bindings/java/src/org/hyperic/sigar/cmd/Shell.java

@@ -103,6 +103,8 @@ public class Shell extends ShellBase {
         registerCommandHandler("time", new Time(this));
         registerCommandHandler("ulimit", new Ulimit(this));
         registerCommandHandler("who", new Who(this));
+        registerCommandHandler("pid_cache_info", new PidCacheInfo(this));
+
         if (SigarLoader.IS_WIN32) {
             registerCommandHandler("service", new Win32Service(this));
             registerCommandHandler("fversion", new FileVersionInfo(this));

bindings/java/src/org/hyperic/sigar/jmx/SigarProcess.java

@@ -20,6 +20,7 @@ import org.hyperic.sigar.ProcCpu;
 import org.hyperic.sigar.ProcFd;
 import org.hyperic.sigar.ProcMem;
 import org.hyperic.sigar.ProcUtil;
+import org.hyperic.sigar.ProcDiskIO;
 import org.hyperic.sigar.Sigar;
 import org.hyperic.sigar.SigarException;
 import org.hyperic.sigar.SigarProxy;
@@ -76,6 +77,16 @@ public class SigarProcess implements SigarProcessMBean {
         }   
     }
 
+
+    private synchronized ProcDiskIO getDiskIO() {
+	try {
+            return this.sigar.getProcDiskIO(getPid());
+        } catch (SigarException e) {
+            throw unexpectedError("DiskIO", e);
+        }
+    }
+
+
     private synchronized ProcFd getFd() throws SigarException {
         return this.sigar.getProcFd(getPid());
     }
@@ -153,4 +164,9 @@ public class SigarProcess implements SigarProcessMBean {
             return NOTIMPL;
         }
     }
+
+     public Double getBytesReadWriteTotal() {
+        return new Double(getDiskIO().getBytesTotal());
+    }
+
 }

bindings/java/src/org/hyperic/sigar/jmx/SigarProcessMBean.java

@@ -44,4 +44,6 @@ public interface SigarProcessMBean {
     public Double getCpuUsage();
 
     public Long getOpenFd();
+    
+    public Double getBytesReadWriteTotal();
 }

include/sigar.h

@@ -293,7 +293,7 @@ SIGAR_DECLARE(int) sigar_proc_mem_get(sigar_t *sigar, sigar_pid_t pid,
                                       sigar_proc_mem_t *procmem);
 
 typedef struct {
-    sigar_uint64_t
+     sigar_uint64_t 
         bytes_read,
         bytes_written,
         bytes_total;
@@ -302,6 +302,37 @@ typedef struct {
 SIGAR_DECLARE(int) sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
                                           sigar_proc_disk_io_t *proc_disk_io);
 
+typedef struct {
+    sigar_uint64_t
+        bytes_read,
+        bytes_written,
+        bytes_total;
+    sigar_uint64_t last_time;
+    sigar_uint64_t
+        bytes_read_diff,
+        bytes_written_diff,
+        bytes_total_diff;
+} sigar_cached_proc_disk_io_t;
+
+
+typedef struct {
+    sigar_uint64_t
+        bytes_read,
+        bytes_written,
+        bytes_total;
+} sigar_proc_cumulative_disk_io_t;
+
+SIGAR_DECLARE(int) sigar_proc_cumulative_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
+                                          sigar_proc_cumulative_disk_io_t *proc_cumulative_disk_io);
+
+
+typedef struct  { 
+    sigar_uint64_t dummy;
+}sigar_dump_pid_cache_t;
+
+SIGAR_DECLARE(int) sigar_dump_pid_cache_get(sigar_t *sigar, sigar_dump_pid_cache_t *info);
+
+
 typedef struct {
     sigar_uid_t uid;
     sigar_gid_t gid;

include/sigar_private.h

@@ -68,7 +68,8 @@
    sigar_cache_t *proc_cpu; \
    sigar_cache_t *net_listen; \
    sigar_cache_t *net_services_tcp; \
-   sigar_cache_t *net_services_udp
+   sigar_cache_t *net_services_udp;\
+   sigar_cache_t *proc_io;
 
 #if defined(WIN32)
 #   define SIGAR_INLINE __inline
@@ -398,11 +399,15 @@ int sigar_get_iftype(const char *name, int *type, int *inst);
 #define SIGAR_NIC_SIT      "IPv6-in-IPv4"
 #define SIGAR_NIC_IRDA     "IrLAP"
 #define SIGAR_NIC_EC       "Econet"
-
+#define PID_CACHE_CLEANUP_PERIOD 1000*60*10 /* 10 minutes */
+#define PID_CACHE_ENTRY_EXPIRE_PERIOD 1000*60*20 /* 20 minutes */
 #ifndef WIN32
 #include <netdb.h>
 #endif
 
+#define PROC_PID_CPU_CACHE 1
+#define PROC_PID_IO_CACHE 2
+
 #define SIGAR_HOSTENT_LEN 1024
 #if defined(_AIX)
 #define SIGAR_HAS_HOSTENT_DATA

include/sigar_util.h

@@ -170,15 +170,21 @@ struct sigar_cache_entry_t {
     sigar_cache_entry_t *next;
     sigar_uint64_t id;
     void *value;
+    sigar_uint64_t last_access_time;
 };
 
 typedef struct {
     sigar_cache_entry_t **entries;
     unsigned int count, size;
     void (*free_value)(void *ptr);
+    sigar_uint64_t entry_expire_period;
+    sigar_uint64_t cleanup_period_millis;
+    sigar_uint64_t last_cleanup_time;
 } sigar_cache_t;
 
 sigar_cache_t *sigar_cache_new(int size);
+sigar_cache_t *sigar_expired_cache_new(int size, sigar_uint64_t cleanup_period_millis, sigar_uint64_t entry_expire_period);
+void sigar_cache_dump(sigar_cache_t *table);
 
 sigar_cache_entry_t *sigar_cache_get(sigar_cache_t *table,
                                      sigar_uint64_t key);

src/os/aix/aix_sigar.c

@@ -754,8 +754,8 @@ int sigar_proc_mem_get(sigar_t *sigar, sigar_pid_t pid,
     return SIGAR_OK;
 }
 
-int sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
+int sigar_proc_cumulative_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
-                           sigar_proc_disk_io_t *proc_disk_io)
+                           sigar_proc_cumulative_disk_io_t *cumulative_proc_disk_io)
 {
     int status = sigar_getprocs(sigar, pid);
     struct procsinfo64 *pinfo = sigar->pinfo;
@@ -763,13 +763,11 @@ int sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
     if (status != SIGAR_OK) {
         return status;
     }
-    proc_disk_io->bytes_read = SIGAR_FIELD_NOTIMPL;
+    cumulative_proc_disk_io->bytes_read = SIGAR_FIELD_NOTIMPL;
-    proc_disk_io->bytes_written =  SIGAR_FIELD_NOTIMPL;
+    cumulative_proc_disk_io->bytes_written =  SIGAR_FIELD_NOTIMPL;
-    proc_disk_io->bytes_total = pinfo->pi_ioch;
+    cumulative_proc_disk_io->bytes_total = pinfo->pi_ioch;
 
     return SIGAR_OK;
-
-
 }
 
 

src/os/darwin/darwin_sigar.c

@@ -1241,8 +1241,8 @@ int sigar_proc_mem_get(sigar_t *sigar, sigar_pid_t pid,
     return SIGAR_OK;
 }
 
-int sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
+int sigar_proc_cumulative_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
-                           sigar_proc_disk_io_t *proc_disk_io)
+                           sigar_proc_cumulative_disk_io_t *proc_cumulative_disk_io)
 {
     return SIGAR_ENOTIMPL;
 }

src/os/hpux/hpux_sigar.c

@@ -307,8 +307,8 @@ int sigar_proc_mem_get(sigar_t *sigar, sigar_pid_t pid,
     return SIGAR_OK;
 }
 
-int sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid, 
+int sigar_proc_cumulative_disk_io_get(sigar_t *sigar, sigar_pid_t pid, 
-                           sigar_proc_disk_io_t *proc_disk_io)
+                           sigar_proc_cumulative_disk_io_t *proc_cumulative_disk_io)
 {
 
     int status = sigar_pstat_getproc(sigar, pid);
@@ -317,9 +317,9 @@ int sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
     if (status != SIGAR_OK) {
         return status;
     }
-    proc_disk_io->bytes_read = SIGAR_FIELD_NOTIMPL; 
+    proc_cumulative_disk_io->bytes_read = SIGAR_FIELD_NOTIMPL; 
-    proc_disk_io->bytes_written = SIGAR_FIELD_NOTIMPL; 
+    proc_cumulative_disk_io->bytes_written = SIGAR_FIELD_NOTIMPL; 
-    proc_disk_io->bytes_total =  pinfo->pst_ioch;
+    proc_cumulative_disk_io->bytes_total =  pinfo->pst_ioch;
 
 
    return SIGAR_OK;

src/os/linux/linux_sigar.c

@@ -778,10 +778,10 @@ SIGAR_INLINE sigar_uint64_t get_named_proc_token(char *buffer,
   return sigar_strtoul(ptr);
 }
 
-int sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
+int sigar_proc_cumulative_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
-                           sigar_proc_disk_io_t *proc_disk_io)
+                           sigar_proc_cumulative_disk_io_t *proc_cumulative_disk_io)
 {
-    char buffer[BUFSIZ], *ptr=buffer;
+    char buffer[BUFSIZ];
     
     int status = SIGAR_PROC_FILE2STR(buffer, pid, "/io");
     
@@ -789,9 +789,9 @@ int sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
         return status;
     }
 
-    proc_disk_io->bytes_read = get_named_proc_token(buffer, "\nread_bytes");
+    proc_cumulative_disk_io->bytes_read = get_named_proc_token(buffer, "\nread_bytes");
-    proc_disk_io->bytes_written = get_named_proc_token(buffer, "\nwrite_bytes");
+    proc_cumulative_disk_io->bytes_written = get_named_proc_token(buffer, "\nwrite_bytes");
-    proc_disk_io->bytes_total = proc_disk_io->bytes_read + proc_disk_io->bytes_written;
+    proc_cumulative_disk_io->bytes_total = proc_cumulative_disk_io->bytes_read + proc_cumulative_disk_io->bytes_written;
 
     return SIGAR_OK;
 }

src/os/solaris/solaris_sigar.c

@@ -407,7 +407,7 @@ int sigar_cpu_get(sigar_t *sigar, sigar_cpu_t *cpu)
         cpu->idle  += xcpu->idle;
         cpu->nice  += xcpu->nice;
         cpu->wait  += xcpu->wait;
-        cpu->total = xcpu->total;
+        cpu->total += xcpu->total;
     }
 
     return SIGAR_OK;
@@ -719,17 +719,17 @@ int sigar_proc_mem_get(sigar_t *sigar, sigar_pid_t pid,
     return SIGAR_OK;
 }
 
-int sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid, 
+int sigar_proc_cumulative_disk_io_get(sigar_t *sigar, sigar_pid_t pid, 
-                           sigar_proc_disk_io_t *proc_disk_io)
+                           sigar_proc_cumulative_disk_io_t *proc_cumulative_disk_io)
 {
    prusage_t usage;
    int status;
    if ((status = sigar_proc_usage_get(sigar, &usage, pid)) != SIGAR_OK) {
         return status;
    }
-   proc_disk_io->bytes_read = SIGAR_FIELD_NOTIMPL;
+   proc_cumulative_disk_io->bytes_read = SIGAR_FIELD_NOTIMPL;
-   proc_disk_io->bytes_written = SIGAR_FIELD_NOTIMPL;
+   proc_cumulative_disk_io->bytes_written = SIGAR_FIELD_NOTIMPL;
-   proc_disk_io->bytes_total =  usage.pr_ioch;
+   proc_cumulative_disk_io->bytes_total =  usage.pr_ioch;
 
     return SIGAR_OK;
 }

src/os/win32/win32_sigar.c

@@ -1214,8 +1214,8 @@ SIGAR_DECLARE(int) sigar_proc_mem_get(sigar_t *sigar, sigar_pid_t pid,
     return SIGAR_OK;
 }
 
-SIGAR_DECLARE(int) sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
+SIGAR_DECLARE(int) sigar_proc_cumulative_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
-                                          sigar_proc_disk_io_t *proc_disk_io)
+                                          sigar_proc_cumulative_disk_io_t *proc_cumulative_disk_io)
 {
     int status = get_proc_info(sigar, pid);
     sigar_win32_pinfo_t *pinfo = &sigar->pinfo;
@@ -1224,9 +1224,9 @@ SIGAR_DECLARE(int) sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
         return status;
     }
 
-    proc_disk_io->bytes_read = pinfo->bytes_read;
+    proc_cumulative_disk_io->bytes_read = pinfo->bytes_read;
-    proc_disk_io->bytes_written = pinfo->bytes_written;
+    proc_cumulative_disk_io->bytes_written = pinfo->bytes_written;
-    proc_disk_io->bytes_total = proc_disk_io->bytes_read + proc_disk_io->bytes_written;
+    proc_cumulative_disk_io->bytes_total = proc_cumulative_disk_io->bytes_read + proc_cumulative_disk_io->bytes_written;
 
     return SIGAR_OK;
 }

src/sigar.c

@@ -64,6 +64,7 @@ SIGAR_DECLARE(int) sigar_open(sigar_t **sigar)
         (*sigar)->net_listen = NULL;
         (*sigar)->net_services_tcp = NULL;
         (*sigar)->net_services_udp = NULL;
+	(*sigar)->proc_io = NULL;
     }
 
     return status;
@@ -96,6 +97,11 @@ SIGAR_DECLARE(int) sigar_close(sigar_t *sigar)
     if (sigar->net_services_udp) {
         sigar_cache_destroy(sigar->net_services_udp);
     }
+    if (sigar->proc_io) {
+        sigar_cache_destroy(sigar->proc_io);
+    }
+
+
 
     return sigar_os_close(sigar);
 }
@@ -123,7 +129,7 @@ SIGAR_DECLARE(int) sigar_proc_cpu_get(sigar_t *sigar, sigar_pid_t pid,
     int status;
 
     if (!sigar->proc_cpu) {
-        sigar->proc_cpu = sigar_cache_new(128);
+        sigar->proc_cpu = sigar_expired_cache_new(128, PID_CACHE_CLEANUP_PERIOD, PID_CACHE_ENTRY_EXPIRE_PERIOD);
     }
 
     entry = sigar_cache_get(sigar->proc_cpu, pid);
@@ -172,6 +178,104 @@ SIGAR_DECLARE(int) sigar_proc_cpu_get(sigar_t *sigar, sigar_pid_t pid,
 
     return SIGAR_OK;
 }
+void copy_cached_disk_io_into_disk_io( sigar_cached_proc_disk_io_t *cached,  sigar_proc_disk_io_t *proc_disk_io) {
+   proc_disk_io->bytes_read = cached->bytes_read_diff;
+   proc_disk_io->bytes_written = cached->bytes_written_diff;
+   proc_disk_io->bytes_total = cached->bytes_total_diff;
+}
+
+sigar_uint64_t get_io_diff(sigar_uint64_t current_value, sigar_uint64_t prev_value,  sigar_uint64_t time_diff) {
+   if ( current_value == SIGAR_FIELD_NOTIMPL ) {
+      return SIGAR_FIELD_NOTIMPL;
+   }
+   double io_diff = (( current_value - prev_value)/(double)time_diff)*SIGAR_MSEC;
+   sigar_uint64_t int_io_diff = (sigar_uint64_t)io_diff;
+   if (int_io_diff >=0) {
+      return int_io_diff;
+   }
+   return 0;
+}
+
+void calculate_io_diff(sigar_proc_cumulative_disk_io_t * proc_disk_io, sigar_cached_proc_disk_io_t *cached,  sigar_uint64_t time_diff, int is_first_time) {
+   /*calculate avg diff /read/write/total per second*/
+   if (!is_first_time) {
+       cached->bytes_written_diff = get_io_diff(proc_disk_io->bytes_written, cached->bytes_written, time_diff);
+       cached->bytes_read_diff = get_io_diff(proc_disk_io->bytes_read, cached->bytes_read, time_diff);
+       cached->bytes_total_diff = get_io_diff(proc_disk_io->bytes_total, cached->bytes_total, time_diff);
+   }
+   else {
+       cached->bytes_total_diff =  cached->bytes_read_diff =  cached->bytes_written_diff = 0.0;
+   }
+   // now put in cache the current cumulative values
+   cached->bytes_written = proc_disk_io->bytes_written;
+   cached->bytes_read = proc_disk_io->bytes_read;
+   cached->bytes_total = proc_disk_io->bytes_total;
+}
+
+SIGAR_DECLARE(int) sigar_proc_disk_io_get(sigar_t *sigar, sigar_pid_t pid,
+                                          sigar_proc_disk_io_t *proc_disk_io)
+{
+    sigar_cache_entry_t *entry;
+    sigar_cached_proc_disk_io_t *prev;
+    sigar_proc_cumulative_disk_io_t  cumulative_proc_disk_io;
+    sigar_uint64_t time_now = sigar_time_now_millis();
+    sigar_uint64_t time_diff;
+    int status;
+
+    if (!sigar->proc_io) {
+        sigar->proc_io =  sigar_expired_cache_new(128, PID_CACHE_CLEANUP_PERIOD, PID_CACHE_ENTRY_EXPIRE_PERIOD);
+    }
+
+    entry = sigar_cache_get(sigar->proc_io, pid);
+    if (entry->value) {
+        prev = (sigar_cached_proc_disk_io_t *)entry->value;
+    }
+    else {
+        prev = entry->value = malloc(sizeof(*prev));
+        SIGAR_ZERO(prev);
+    }
+    int is_first_time = (prev->last_time == 0);
+    time_diff = time_now - prev->last_time;
+
+    if (time_diff < 1000) {
+        /* we were just called within < 1 second ago. */
+        copy_cached_disk_io_into_disk_io(prev, proc_disk_io);
+	if (time_diff < 0) {
+	   // something is wrong at least from now on the time will be ok
+ 	   prev->last_time = time_now;
+        }
+        return SIGAR_OK;
+    }
+    prev->last_time = time_now;
+
+
+    status =
+        sigar_proc_cumulative_disk_io_get(sigar, pid,
+                            &cumulative_proc_disk_io);
+
+    if (status != SIGAR_OK) {
+        return status;
+    }
+    calculate_io_diff(&cumulative_proc_disk_io, prev, time_diff,  is_first_time);
+    copy_cached_disk_io_into_disk_io(prev, proc_disk_io);
+    return SIGAR_OK;
+}
+
+void get_cache_info(sigar_cache_t * cache, char * name){
+   if (cache == NULL) {
+      return;
+   }
+
+   printf("******** %s *********\n", name);
+   sigar_cache_dump(cache);
+}
+
+SIGAR_DECLARE(int) sigar_dump_pid_cache_get(sigar_t *sigar, sigar_dump_pid_cache_t *info) {
+  
+  get_cache_info(sigar->proc_cpu, "proc cpu cache");
+  get_cache_info(sigar->proc_io, "proc io cache");
+  return SIGAR_OK;
+}
 
 SIGAR_DECLARE(int) sigar_proc_stat_get(sigar_t *sigar,
                                        sigar_proc_stat_t *procstat)

src/sigar_cache.c

@@ -35,7 +35,7 @@ static void free_value(void *ptr)
     free(ptr);
 }
 
-sigar_cache_t *sigar_cache_new(int size)
+sigar_cache_t *sigar_expired_cache_new(int size, sigar_uint64_t cleanup_period_millis, sigar_uint64_t entry_expire_period)
 {
     sigar_cache_t *table = malloc(sizeof(*table));
     table->count = 0;
@@ -43,16 +43,27 @@ sigar_cache_t *sigar_cache_new(int size)
     table->entries = malloc(ENTRIES_SIZE(size));
     memset(table->entries, '\0', ENTRIES_SIZE(size));
     table->free_value = free_value;
+    table->cleanup_period_millis = cleanup_period_millis;
+    table->last_cleanup_time = sigar_time_now_millis();
+    table->entry_expire_period = entry_expire_period;
     return table;
 }
 
-#ifdef DEBUG_CACHE
+sigar_cache_t *sigar_cache_new(int size)
+{
+    return sigar_expired_cache_new(size, SIGAR_FIELD_NOTIMPL, SIGAR_FIELD_NOTIMPL);
+}
+
+
+/*#ifdef DEBUG_CACHE*/
 /* see how well entries are distributed */
-static void sigar_cache_dump(sigar_cache_t *table)
+void sigar_cache_dump(sigar_cache_t *table)
 {
     int i;
     sigar_cache_entry_t **entries = table->entries;
-
+    printf("table size %lu\n", (long)table->size); 
+    printf("table count %lu\n", (long)table->count);
+    
     for (i=0; i<table->size; i++) {
         sigar_cache_entry_t *entry = *entries++;
 
@@ -68,12 +79,12 @@ static void sigar_cache_dump(sigar_cache_t *table)
     printf("\n");
     fflush(stdout);
 }
-#endif
+/*#endif*/
 
 static void sigar_cache_rehash(sigar_cache_t *table)
 {
     int i;
-    unsigned int new_size = table->size * 2 + 1;
+    unsigned int new_size = table->count * 2 + 1;
     sigar_cache_entry_t **entries = table->entries;
     sigar_cache_entry_t **new_entries =
         malloc(ENTRIES_SIZE(new_size));
@@ -101,16 +112,73 @@ static void sigar_cache_rehash(sigar_cache_t *table)
 #define SIGAR_CACHE_IX(t, k) \
     t->entries + (k % t->size)
 
+void sigar_perform_cleanup_if_necessary(sigar_cache_t *table) { 
+    if (table->cleanup_period_millis == SIGAR_FIELD_NOTIMPL) {
+ 	/* no cleanup for this cache) */
+    }
+    sigar_uint64_t current_time = sigar_time_now_millis();
+    if ((current_time - table->last_cleanup_time) < table->cleanup_period_millis) {
+        /* not enough time has passed since last cleanup */
+        return;
+    }	
+
+    /* performing cleanup */
+    int i;
+    sigar_cache_entry_t **entries = table->entries;
+
+    table->last_cleanup_time = current_time;
+    
+    for (i=0; i<table->size; i++) {
+        sigar_cache_entry_t *entry, *ptr, *entry_prev=NULL, **entry_in_table;
+        entry_in_table = entries;
+        entry = *entries++;
+
+        while (entry) {
+            ptr = entry->next;
+            sigar_uint64_t period_with_no_access = current_time - entry->last_access_time;
+            if (table->entry_expire_period < period_with_no_access) {
+		/* no one acess this entry for too long - we can delete it */
+	        if (entry->value) {
+                   table->free_value(entry->value);
+                } 
+                free(entry);
+		table->count--;
+                if (entry_prev != NULL) {
+                   entry_prev->next = ptr;
+                }
+                else {
+                   /* removing first entry - head of list should point to next entry */               
+                   *entry_in_table = ptr;
+                } 
+            }
+            else {
+              /* entry not expired - advance entry_prev to current entry*/
+              entry_prev = entry;
+	    }
+            entry = ptr;
+        }
+    }
+    if (table->count < (table->size/4)) {
+	/* hash table (the array size) too big for the amount of values it contains perform rehash */
+        sigar_cache_rehash(table);
+    }
+}
+
+   
+
+
 sigar_cache_entry_t *sigar_cache_find(sigar_cache_t *table,
                                       sigar_uint64_t key)
 {
     sigar_cache_entry_t *entry, **ptr;
+    sigar_perform_cleanup_if_necessary(table);
 
     for (ptr = SIGAR_CACHE_IX(table, key), entry = *ptr;
          entry;
          ptr = &entry->next, entry = *ptr)
     {
         if (entry->id == key) {
+            entry->last_access_time = sigar_time_now_millis();
             return entry;
         }
     }
@@ -123,17 +191,19 @@ sigar_cache_entry_t *sigar_cache_get(sigar_cache_t *table,
                                      sigar_uint64_t key)
 {
     sigar_cache_entry_t *entry, **ptr;
+    sigar_perform_cleanup_if_necessary(table);
 
     for (ptr = SIGAR_CACHE_IX(table, key), entry = *ptr;
          entry;
          ptr = &entry->next, entry = *ptr)
     {
         if (entry->id == key) {
+            entry->last_access_time = sigar_time_now_millis();
             return entry;
         }
     }
 
-    if (table->count++ > table->size) {
+    if (++table->count > table->size) {
         sigar_cache_rehash(table);
 
         for (ptr = SIGAR_CACHE_IX(table, key), entry = *ptr;
@@ -147,6 +217,7 @@ sigar_cache_entry_t *sigar_cache_get(sigar_cache_t *table,
     entry->id = key;
     entry->value = NULL;
     entry->next = NULL;
+    entry->last_access_time = sigar_time_now_millis();
 
     return entry;
 }

src/sigar_ptql.c

@@ -1338,6 +1338,14 @@ static ptql_lookup_t PTQL_Cpu[] = {
     { NULL }
 };
 
+static ptql_lookup_t PTQL_Disk_IO[] = {
+    { "BytesRead", PTQL_LOOKUP_ENTRY(proc_disk_io, bytes_read, UI64) },
+    { "BytesWritten",      PTQL_LOOKUP_ENTRY(proc_disk_io, bytes_written, UI64) },
+    { "BytesTotal",       PTQL_LOOKUP_ENTRY(proc_disk_io, bytes_total, UI64) },
+    { NULL }
+};
+
+
 static ptql_lookup_t PTQL_CredName[] = {
     { "User",  PTQL_LOOKUP_ENTRY(proc_cred_name, user, STR) },
     { "Group", PTQL_LOOKUP_ENTRY(proc_cred_name, group, STR) },
@@ -1424,6 +1432,7 @@ static ptql_entry_t ptql_map[] = {
     { "Port",     PTQL_Port },
     { "Pid",      PTQL_Pid },
     { "Service",  PTQL_Service },
+    { "Disk_IO",   PTQL_Disk_IO },
     { NULL }
 };