0526のＨｏｍｅｗｏｒｋ

1.Experimentally construct a rough memory map for an application on your operating system.

1. Write a program that prints out (in hexadecimal) the addresses of the following:
   1. main()
   2. a variable on the outermost stack frame (main()'s stack frame)
   3. a variable on the stack frame of a recursively-called function called to a depth of five times
   4. a statically-defined but uninitialized variable
   5. a statically-defined, initialized variable
   6. several large chunks of malloc()ed memory
   7. a library routine, such as strcpy()
   8. a system call wrapper, such as the one for write()

[プログラム]
1 #include
2 #include
3 #include
4 #include
5
6 void recursive_function();
7
8 static cnt = 5;
9
10 int main(int argc, char **argv)
11 {
12 static uninitial;
13 static initial=0;
14 int *mem, a;
15 mem = (int *)malloc(16);
16 char *src = "hello";
17 char *dst;
18
19 printf(" main() : %p\n", main);
20 printf(" argc : %p\n a: %p\n", &argc, &a);
21 printf(" recursive_function : %p\n", recursive_function);
22 printf(" uninitial : %p\n", &uninitial);
23 printf(" initial : %p\n", &initial);
24 printf(" malloc : %p\n", &mem);
25 printf(" strcpy : %p\n", strcpy(dst, src));
26 printf("system call wrapper : %p\n", fork);
27
28 }
29
30 void
31 recursive_function()
32 {
33 if (cnt < 0) {
34 return ;
35 }
36 cnt--;
37 recursive_function();
38 }
[実行結果]
main() : 0x8048414
argc : 0xbff2e450
a : 0xbff2e428
recursive_function : 0x804850d
uninitial : 0x8049808
initial : 0x8049804
malloc : 0x804a020
strcpy : 0xb7f73ff4
system call wrapper : 0x8048378

B. Take that information and draw a memory map for your OS. It should indicate which direction the stack and the heap grow in. An ASCII picture is okay, or you can use a drawing program of some sort if you wish.

1. How big is the distance between your stack and your heap?
2. Was your program compiled with static libraries or shared libraries?

1.メモリ番地を計算すると0xbf829a26の距離が有ります

2.strcpyは共有ライブラリで、他の関数(main, recursive)は静的ライブラリ（？）


2.
A.デバイスドライバ内で記述されているinterrupt coalescing
/* Get the coalescing parameters, and put them in the cvals
* structure. */
static int gfar_gcoalesce(struct net_device *dev, struct ethtool_coalesce *cvals)
{
struct gfar_private *priv = netdev_priv(dev);

if (!(priv->einfo->device_flags & FSL_GIANFAR_DEV_HAS_COALESCE))
return -EOPNOTSUPP;

if (NULL == priv->phydev)
return -ENODEV;

cvals->rx_coalesce_usecs = gfar_ticks2usecs(priv, priv->rxtime);
cvals->rx_max_coalesced_frames = priv->rxcount;

cvals->tx_coalesce_usecs = gfar_ticks2usecs(priv, priv->txtime);
cvals->tx_max_coalesced_frames = priv->txcount;

cvals->use_adaptive_rx_coalesce = 0;
cvals->use_adaptive_tx_coalesce = 0;

cvals->pkt_rate_low = 0;
cvals->rx_coalesce_usecs_low = 0;
cvals->rx_max_coalesced_frames_low = 0;
cvals->tx_coalesce_usecs_low = 0;
cvals->tx_max_coalesced_frames_low = 0;

/* When the packet rate is below pkt_rate_high but above
* pkt_rate_low (both measured in packets per second) the
* normal {rx,tx}_* coalescing parameters are used.
*/

/* When the packet rate is (measured in packets per second)
* is above pkt_rate_high, the {rx,tx}_*_high parameters are
* used.
*/
cvals->pkt_rate_high = 0;
cvals->rx_coalesce_usecs_high = 0;
cvals->rx_max_coalesced_frames_high = 0;
cvals->tx_coalesce_usecs_high = 0;
cvals->tx_max_coalesced_frames_high = 0;

/* How often to do adaptive coalescing packet rate sampling,
* measured in seconds. Must not be zero.
*/
cvals->rate_sample_interval = 0;

return 0;
}

/* Change the coalescing values.
* Both cvals->*_usecs and cvals->*_frames have to be > 0
* in order for coalescing to be active
*/
static int gfar_scoalesce(struct net_device *dev, struct ethtool_coalesce *cvals)
{
struct gfar_private *priv = netdev_priv(dev);

if (!(priv->einfo->device_flags & FSL_GIANFAR_DEV_HAS_COALESCE))
return -EOPNOTSUPP;

/* Set up rx coalescing */
if ((cvals->rx_coalesce_usecs == 0) ||
(cvals->rx_max_coalesced_frames == 0))
priv->rxcoalescing = 0;
else
priv->rxcoalescing = 1;

if (NULL == priv->phydev)
return -ENODEV;

/* Check the bounds of the values */
if (cvals->rx_coalesce_usecs > GFAR_MAX_COAL_USECS) {
pr_info("Coalescing is limited to %d microseconds\n",
GFAR_MAX_COAL_USECS);
return -EINVAL;
}

if (cvals->rx_max_coalesced_frames > GFAR_MAX_COAL_FRAMES) {
pr_info("Coalescing is limited to %d frames\n",
GFAR_MAX_COAL_FRAMES);
return -EINVAL;
}

priv->rxtime = gfar_usecs2ticks(priv, cvals->rx_coalesce_usecs);
priv->rxcount = cvals->rx_max_coalesced_frames;

/* Set up tx coalescing */
if ((cvals->tx_coalesce_usecs == 0) ||
(cvals->tx_max_coalesced_frames == 0))
priv->txcoalescing = 0;
else
priv->txcoalescing = 1;

/* Check the bounds of the values */
if (cvals->tx_coalesce_usecs > GFAR_MAX_COAL_USECS) {
pr_info("Coalescing is limited to %d microseconds\n",
GFAR_MAX_COAL_USECS);
return -EINVAL;
}

if (cvals->tx_max_coalesced_frames > GFAR_MAX_COAL_FRAMES) {
pr_info("Coalescing is limited to %d frames\n",
GFAR_MAX_COAL_FRAMES);
return -EINVAL;
}

priv->txtime = gfar_usecs2ticks(priv, cvals->tx_coalesce_usecs);
priv->txcount = cvals->tx_max_coalesced_frames;

if (priv->rxcoalescing)
gfar_write(&priv->regs->rxic,
mk_ic_value(priv->rxcount, priv->rxtime));
else
gfar_write(&priv->regs->rxic, 0);

if (priv->txcoalescing)
gfar_write(&priv->regs->txic,
mk_ic_value(priv->txcount, priv->txtime));
else
gfar_write(&priv->regs->txic, 0);

return 0;
}

B. HPのマシン2台、GbitのNICを持っている。またethtool -C eth0を実行出来る
ただまだcoalescingの設定変更は出来ていない。
Packetモニター用のThinkpadのPCのNICもGbitのNICを持っている。

C. milestone & schedule
6/2 マシンの性能確認＆coalescingのデバイスドライバでの実装を見る
6/9 interrupt coalescingの設定方法を見つける＆実験環境を整える
6/16 iperfへのCPU時間取得コードの実装＆packet間の時間の測定
6/23 CPU時間の精度を求める＆測定開始
6/30 coalescingを変更したときのCPU時間の測定とpacketロスの測定の終了(CPUに制限を与えた場合)
7/7 考察


3.
4 hours