[Qemu-devel] [PATCH v4 0/3] slirp: fill mainloop with more precise timeout value

[Qemu-devel] [PATCH v4 0/3] slirp: fill mainloop with more precise timeout value

[Liu Ping Fan]

With this series, we can set the mainloop timeout more precisely when slirp has
to emulate tcp timeout problem.

v4:
  use macro TIMEOUT_DEFAULT to define the default timeout of slirp and document it.

v3:
  fix comment: document timeout unit "milliseconds"
  fix logic: no slirps, no timeout modifications in slirp_pollfds_fill()
v2:
  fold slirp_update_timeout logic into slirp_pollfds_fill.


Liu Ping Fan (3):
  slirp: make timeout local
  slirp: define timeout as macro
  slirp: set mainloop timeout with more precise value

 main-loop.c      |  3 +--
 slirp/libslirp.h |  3 +--
 slirp/slirp.c    | 61 +++++++++++++++++++++++++++++++++++++++-----------------
 slirp/slirp.h    |  3 +++
 stubs/slirp.c    |  6 +-----
 5 files changed, 49 insertions(+), 27 deletions(-)

-- 
1.8.1.4

[Qemu-devel] [PATCH v4 1/3] slirp: make timeout local

[Liu Ping Fan]

Each slirp has its own time to caculate timeout.

Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
---
 slirp/slirp.c | 22 ++++++++++------------
 slirp/slirp.h |  3 +++
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/slirp/slirp.c b/slirp/slirp.c
index 80b28ea..b71c617 100644
--- a/slirp/slirp.c
+++ b/slirp/slirp.c
@@ -40,8 +40,6 @@ static const uint8_t special_ethaddr[ETH_ALEN] = {
 static const uint8_t zero_ethaddr[ETH_ALEN] = { 0, 0, 0, 0, 0, 0 };
 
 u_int curtime;
-static u_int time_fasttimo, last_slowtimo;
-static int do_slowtimo;
 
 static QTAILQ_HEAD(slirp_instances, Slirp) slirp_instances =
     QTAILQ_HEAD_INITIALIZER(slirp_instances);
@@ -278,14 +276,13 @@ void slirp_pollfds_fill(GArray *pollfds)
     /*
      * First, TCP sockets
      */
-    do_slowtimo = 0;
 
     QTAILQ_FOREACH(slirp, &slirp_instances, entry) {
         /*
          * *_slowtimo needs calling if there are IP fragments
          * in the fragment queue, or there are TCP connections active
          */
-        do_slowtimo |= ((slirp->tcb.so_next != &slirp->tcb) ||
+        slirp->do_slowtimo = ((slirp->tcb.so_next != &slirp->tcb) ||
                 (&slirp->ipq.ip_link != slirp->ipq.ip_link.next));
 
         for (so = slirp->tcb.so_next; so != &slirp->tcb;
@@ -299,8 +296,9 @@ void slirp_pollfds_fill(GArray *pollfds)
             /*
              * See if we need a tcp_fasttimo
              */
-            if (time_fasttimo == 0 && so->so_tcpcb->t_flags & TF_DELACK) {
-                time_fasttimo = curtime; /* Flag when we want a fasttimo */
+            if (slirp->time_fasttimo == 0 &&
+                so->so_tcpcb->t_flags & TF_DELACK) {
+                slirp->time_fasttimo = curtime; /* Flag when want a fasttimo */
             }
 
             /*
@@ -381,7 +379,7 @@ void slirp_pollfds_fill(GArray *pollfds)
                     udp_detach(so);
                     continue;
                 } else {
-                    do_slowtimo = 1; /* Let socket expire */
+                    slirp->do_slowtimo = true; /* Let socket expire */
                 }
             }
 
@@ -422,7 +420,7 @@ void slirp_pollfds_fill(GArray *pollfds)
                     icmp_detach(so);
                     continue;
                 } else {
-                    do_slowtimo = 1; /* Let socket expire */
+                    slirp->do_slowtimo = true; /* Let socket expire */
                 }
             }
 
@@ -454,14 +452,14 @@ void slirp_pollfds_poll(GArray *pollfds, int select_error)
         /*
          * See if anything has timed out
          */
-        if (time_fasttimo && ((curtime - time_fasttimo) >= 2)) {
+        if (slirp->time_fasttimo && ((curtime - slirp->time_fasttimo) >= 2)) {
             tcp_fasttimo(slirp);
-            time_fasttimo = 0;
+            slirp->time_fasttimo = 0;
         }
-        if (do_slowtimo && ((curtime - last_slowtimo) >= 499)) {
+        if (slirp->do_slowtimo && ((curtime - slirp->last_slowtimo) >= 499)) {
             ip_slowtimo(slirp);
             tcp_slowtimo(slirp);
-            last_slowtimo = curtime;
+            slirp->last_slowtimo = curtime;
         }
 
         /*
diff --git a/slirp/slirp.h b/slirp/slirp.h
index fe0e65d..e4a1bd4 100644
--- a/slirp/slirp.h
+++ b/slirp/slirp.h
@@ -203,6 +203,9 @@ bool arp_table_search(Slirp *slirp, uint32_t ip_addr,
 
 struct Slirp {
     QTAILQ_ENTRY(Slirp) entry;
+    u_int time_fasttimo;
+    u_int last_slowtimo;
+    bool do_slowtimo;
 
     /* virtual network configuration */
     struct in_addr vnetwork_addr;
-- 
1.8.1.4

[Qemu-devel] [PATCH v4 2/3] slirp: define timeout as macro

[Liu Ping Fan]

Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
---
 slirp/slirp.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/slirp/slirp.c b/slirp/slirp.c
index b71c617..c47af8f 100644
--- a/slirp/slirp.c
+++ b/slirp/slirp.c
@@ -47,6 +47,11 @@ static QTAILQ_HEAD(slirp_instances, Slirp) slirp_instances =
 static struct in_addr dns_addr;
 static u_int dns_addr_time;
 
+#define TIMEOUT_FAST 2  /* milliseconds */
+#define TIMEOUT_SLOW 499  /* milliseconds */
+/* for the aging of certain requests like DNS */
+#define TIMEOUT_DEFAULT 1000  /* milliseconds */
+
 #ifdef _WIN32
 
 int get_dns_addr(struct in_addr *pdns_addr)
@@ -57,7 +62,7 @@ int get_dns_addr(struct in_addr *pdns_addr)
     IP_ADDR_STRING *pIPAddr;
     struct in_addr tmp_addr;
 
-    if (dns_addr.s_addr != 0 && (curtime - dns_addr_time) < 1000) {
+    if (dns_addr.s_addr != 0 && (curtime - dns_addr_time) < TIMEOUT_DEFAULT) {
         *pdns_addr = dns_addr;
         return 0;
     }
@@ -113,7 +118,7 @@ int get_dns_addr(struct in_addr *pdns_addr)
 
     if (dns_addr.s_addr != 0) {
         struct stat old_stat;
-        if ((curtime - dns_addr_time) < 1000) {
+        if ((curtime - dns_addr_time) < TIMEOUT_DEFAULT) {
             *pdns_addr = dns_addr;
             return 0;
         }
@@ -260,7 +265,7 @@ void slirp_cleanup(Slirp *slirp)
 void slirp_update_timeout(uint32_t *timeout)
 {
     if (!QTAILQ_EMPTY(&slirp_instances)) {
-        *timeout = MIN(1000, *timeout);
+        *timeout = MIN(TIMEOUT_DEFAULT, *timeout);
     }
 }
 
@@ -452,11 +457,13 @@ void slirp_pollfds_poll(GArray *pollfds, int select_error)
         /*
          * See if anything has timed out
          */
-        if (slirp->time_fasttimo && ((curtime - slirp->time_fasttimo) >= 2)) {
+        if (slirp->time_fasttimo &&
+            ((curtime - slirp->time_fasttimo) >= TIMEOUT_FAST)) {
             tcp_fasttimo(slirp);
             slirp->time_fasttimo = 0;
         }
-        if (slirp->do_slowtimo && ((curtime - slirp->last_slowtimo) >= 499)) {
+        if (slirp->do_slowtimo &&
+            ((curtime - slirp->last_slowtimo) >= TIMEOUT_SLOW)) {
             ip_slowtimo(slirp);
             tcp_slowtimo(slirp);
             slirp->last_slowtimo = curtime;
-- 
1.8.1.4

[Qemu-devel] [PATCH v4 3/3] slirp: set mainloop timeout with more precise value

[Liu Ping Fan]

If slirp needs to emulate tcp timeout, then the timeout value
for mainloop should be more precise, which is determined by
slirp's fasttimo or slowtimo. Achieve this by swap the logic
sequence of slirp_pollfds_fill and slirp_update_timeout.

Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
---
 main-loop.c      |  3 +--
 slirp/libslirp.h |  3 +--
 slirp/slirp.c    | 28 ++++++++++++++++++++++++----
 stubs/slirp.c    |  6 +-----
 4 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/main-loop.c b/main-loop.c
index a44fff6..e258567 100644
--- a/main-loop.c
+++ b/main-loop.c
@@ -458,8 +458,7 @@ int main_loop_wait(int nonblocking)
     g_array_set_size(gpollfds, 0); /* reset for new iteration */
     /* XXX: separate device handlers from system ones */
 #ifdef CONFIG_SLIRP
-    slirp_update_timeout(&timeout);
-    slirp_pollfds_fill(gpollfds);
+    slirp_pollfds_fill(gpollfds, &timeout);
 #endif
     qemu_iohandler_fill(gpollfds);
     ret = os_host_main_loop_wait(timeout);
diff --git a/slirp/libslirp.h b/slirp/libslirp.h
index ceabff8..5bdcbd5 100644
--- a/slirp/libslirp.h
+++ b/slirp/libslirp.h
@@ -16,8 +16,7 @@ Slirp *slirp_init(int restricted, struct in_addr vnetwork,
                   void *opaque);
 void slirp_cleanup(Slirp *slirp);
 
-void slirp_update_timeout(uint32_t *timeout);
-void slirp_pollfds_fill(GArray *pollfds);
+void slirp_pollfds_fill(GArray *pollfds, uint32_t *timeout);
 
 void slirp_pollfds_poll(GArray *pollfds, int select_error);
 
diff --git a/slirp/slirp.c b/slirp/slirp.c
index c47af8f..63976dc 100644
--- a/slirp/slirp.c
+++ b/slirp/slirp.c
@@ -262,14 +262,33 @@ void slirp_cleanup(Slirp *slirp)
 #define CONN_CANFSEND(so) (((so)->so_state & (SS_FCANTSENDMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
 #define CONN_CANFRCV(so) (((so)->so_state & (SS_FCANTRCVMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
 
-void slirp_update_timeout(uint32_t *timeout)
+static void slirp_update_timeout(uint32_t *timeout)
 {
-    if (!QTAILQ_EMPTY(&slirp_instances)) {
-        *timeout = MIN(TIMEOUT_DEFAULT, *timeout);
+    Slirp *slirp;
+    uint32_t t;
+
+    if (*timeout <= TIMEOUT_FAST) {
+        return;
+    }
+    *timeout = MIN(1000, *timeout);
+    t = *timeout;
+
+    /* If we have tcp timeout with slirp, then we will fill @timeout with
+     * more precise value.
+     */
+    QTAILQ_FOREACH(slirp, &slirp_instances, entry) {
+        if (slirp->time_fasttimo) {
+            *timeout = TIMEOUT_FAST;
+            return;
+        }
+        if (slirp->do_slowtimo) {
+            t = MIN(TIMEOUT_SLOW, t);
+        }
     }
+    *timeout = t;
 }
 
-void slirp_pollfds_fill(GArray *pollfds)
+void slirp_pollfds_fill(GArray *pollfds, uint32_t *timeout)
 {
     Slirp *slirp;
     struct socket *so, *so_next;
@@ -439,6 +458,7 @@ void slirp_pollfds_fill(GArray *pollfds)
             }
         }
     }
+    slirp_update_timeout(timeout);
 }
 
 void slirp_pollfds_poll(GArray *pollfds, int select_error)
diff --git a/stubs/slirp.c b/stubs/slirp.c
index f1fc833..bd0ac7f 100644
--- a/stubs/slirp.c
+++ b/stubs/slirp.c
@@ -1,11 +1,7 @@
 #include "qemu-common.h"
 #include "slirp/slirp.h"
 
-void slirp_update_timeout(uint32_t *timeout)
-{
-}
-
-void slirp_pollfds_fill(GArray *pollfds)
+void slirp_pollfds_fill(GArray *pollfds, uint32_t *timeout)
 {
 }
 
-- 
1.8.1.4

Re: [Qemu-devel] [PATCH v4 0/3] slirp: fill mainloop with more precise timeout value

[Jan Kiszka]

On 2013-08-25 04:01, Liu Ping Fan wrote:
> With this series, we can set the mainloop timeout more precisely when slirp has
> to emulate tcp timeout problem.
> 
> v4:
>   use macro TIMEOUT_DEFAULT to define the default timeout of slirp and document it.
> 
> v3:
>   fix comment: document timeout unit "milliseconds"
>   fix logic: no slirps, no timeout modifications in slirp_pollfds_fill()
> v2:
>   fold slirp_update_timeout logic into slirp_pollfds_fill.
> 
> 
> Liu Ping Fan (3):
>   slirp: make timeout local
>   slirp: define timeout as macro
>   slirp: set mainloop timeout with more precise value
> 
>  main-loop.c      |  3 +--
>  slirp/libslirp.h |  3 +--
>  slirp/slirp.c    | 61 +++++++++++++++++++++++++++++++++++++++-----------------
>  slirp/slirp.h    |  3 +++
>  stubs/slirp.c    |  6 +-----
>  5 files changed, 49 insertions(+), 27 deletions(-)
> 

Thanks, applied to the slirp queue. I'm carrying the tiny cleanup below
on top.

Jan

---

slirp: clean up slirp_update_timeout

No need to write out the timeout early, keep it local until we are done.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 slirp/slirp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/slirp/slirp.c b/slirp/slirp.c
index fe16367..bad8dad 100644
--- a/slirp/slirp.c
+++ b/slirp/slirp.c
@@ -270,8 +270,8 @@ static void slirp_update_timeout(uint32_t *timeout)
     if (*timeout <= TIMEOUT_FAST) {
         return;
     }
-    *timeout = MIN(1000, *timeout);
-    t = *timeout;
+
+    t = MIN(1000, *timeout);
 
     /* If we have tcp timeout with slirp, then we will fill @timeout with
      * more precise value.

-- 
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux