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From: Dario Faggioli <dario.faggioli@citrix.com>
To: xen-devel@lists.xenproject.org
Cc: George Dunlap <george.dunlap@eu.citrix.com>
Subject: [PATCH 8/9] xen/tools: tracing: trace (Credit2) runq traversal.
Date: Thu, 26 Jan 2017 01:30:42 +0100	[thread overview]
Message-ID: <148539064229.5464.13248768128478357532.stgit@Solace.fritz.box> (raw)
In-Reply-To: <148539008889.5464.5896389113741708672.stgit@Solace.fritz.box>

When traversing a Credit2 runqueue to select the
best candidate vCPU to be run next, show in the
trace which vCPUs we consider.

A bit verbose, but quite useful, considering that
we may end up looking at, but then discarding, one
of more vCPU. This will help understand which ones
are skipped and why.

Also, add how much credits the chosen vCPU has
(in the TRC_CSCHED2_RUNQ_CANDIDATE record). And,
while there, fix a bug in tools/xentrace/formats
(still in the output of TRC_CSCHED2_RUNQ_CANDIDATE).

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
---
Cc: George Dunlap <george.dunlap@eu.citrix.com>
---
 tools/xentrace/formats     |    3 ++-
 tools/xentrace/xenalyze.c  |   15 +++++++++++++--
 xen/common/sched_credit2.c |   15 +++++++++++++++
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/tools/xentrace/formats b/tools/xentrace/formats
index db89f92..72c0b24 100644
--- a/tools/xentrace/formats
+++ b/tools/xentrace/formats
@@ -65,9 +65,10 @@
 0x00022210  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  csched2:load_check     [ lrq_id[16]:orq_id[16] = 0x%(1)08x, delta = %(2)d ]
 0x00022211  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  csched2:load_balance   [ l_bavgload = 0x%(2)08x%(1)08x, o_bavgload = 0x%(4)08x%(3)08x, lrq_id[16]:orq_id[16] = 0x%(5)08x ]
 0x00022212  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  csched2:pick_cpu       [ b_avgload = 0x%(2)08x%(1)08x, dom:vcpu = 0x%(3)08x, rq_id[16]:new_cpu[16] = %(4)d ]
-0x00022213  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  csched2:runq_candidate [ dom:vcpu = 0x%(1)08x, skipped_vcpus = %(2)d tickled_cpu = %(3)d ]
+0x00022213  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  csched2:runq_candidate [ dom:vcpu = 0x%(1)08x, credit = %(4)d, skipped_vcpus = %(3)d, tickled_cpu = %(2)d ]
 0x00022214  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  csched2:schedule       [ rq:cpu = 0x%(1)08x, tasklet[8]:idle[8]:smt_idle[8]:tickled[8] = %(2)08x ]
 0x00022215  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  csched2:ratelimit      [ dom:vcpu = 0x%(1)08x, runtime = %(2)d ]
+0x00022216  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  csched2:runq_cand_chk  [ dom:vcpu = 0x%(1)08x ]
 
 0x00022801  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  rtds:tickle        [ cpu = %(1)d ]
 0x00022802  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  rtds:runq_pick     [ dom:vcpu = 0x%(1)08x, cur_deadline = 0x%(3)08x%(2)08x, cur_budget = 0x%(5)08x%(4)08x ]
diff --git a/tools/xentrace/xenalyze.c b/tools/xentrace/xenalyze.c
index a90da20..2678e2a 100644
--- a/tools/xentrace/xenalyze.c
+++ b/tools/xentrace/xenalyze.c
@@ -7825,12 +7825,13 @@ void sched_process(struct pcpu_info *p)
                 struct {
                     unsigned vcpuid:16, domid:16;
                     unsigned tickled_cpu, skipped;
+                    int credit;
                 } *r = (typeof(r))ri->d;
 
-                printf(" %s csched2:runq_candidate d%uv%u, "
+                printf(" %s csched2:runq_candidate d%uv%u, credit = %d, "
                        "%u vcpus skipped, ",
                        ri->dump_header, r->domid, r->vcpuid,
-                       r->skipped);
+                       r->credit, r->skipped);
                 if (r->tickled_cpu == (unsigned)-1)
                     printf("no cpu was tickled\n");
                 else
@@ -7864,6 +7865,16 @@ void sched_process(struct pcpu_info *p)
                        r->runtime / 1000, r->runtime % 1000);
             }
             break;
+        case TRC_SCHED_CLASS_EVT(CSCHED2, 23): /* RUNQ_CAND_CHECK  */
+            if(opt.dump_all) {
+                struct {
+                    unsigned int vcpuid:16, domid:16;
+                } *r = (typeof(r))ri->d;
+
+                printf(" %s csched2:runq_cand_check d%uv%u\n",
+                       ri->dump_header, r->domid, r->vcpuid);
+            }
+            break;
         /* RTDS (TRC_RTDS_xxx) */
         case TRC_SCHED_CLASS_EVT(RTDS, 1): /* TICKLE           */
             if(opt.dump_all) {
diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index 43db669..81149cf 100644
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -57,6 +57,7 @@
 #define TRC_CSCHED2_RUNQ_CANDIDATE   TRC_SCHED_CLASS_EVT(CSCHED2, 20)
 #define TRC_CSCHED2_SCHEDULE         TRC_SCHED_CLASS_EVT(CSCHED2, 21)
 #define TRC_CSCHED2_RATELIMIT        TRC_SCHED_CLASS_EVT(CSCHED2, 22)
+#define TRC_CSCHED2_RUNQ_CAND_CHECK  TRC_SCHED_CLASS_EVT(CSCHED2, 23)
 
 /*
  * WARNING: This is still in an experimental phase.  Status and work can be found at the
@@ -2497,6 +2498,18 @@ runq_candidate(struct csched2_runqueue_data *rqd,
     {
         struct csched2_vcpu * svc = list_entry(iter, struct csched2_vcpu, runq_elem);
 
+        if ( unlikely(tb_init_done) )
+        {
+            struct {
+                unsigned vcpu:16, dom:16;
+            } d;
+            d.dom = svc->vcpu->domain->domain_id;
+            d.vcpu = svc->vcpu->vcpu_id;
+            __trace_var(TRC_CSCHED2_RUNQ_CAND_CHECK, 1,
+                        sizeof(d),
+                        (unsigned char *)&d);
+        }
+
         /* Only consider vcpus that are allowed to run on this processor. */
         if ( !cpumask_test_cpu(cpu, svc->vcpu->cpu_hard_affinity) )
         {
@@ -2545,9 +2558,11 @@ runq_candidate(struct csched2_runqueue_data *rqd,
         struct {
             unsigned vcpu:16, dom:16;
             unsigned tickled_cpu, skipped;
+            int credit;
         } d;
         d.dom = snext->vcpu->domain->domain_id;
         d.vcpu = snext->vcpu->vcpu_id;
+        d.credit = snext->credit;
         d.tickled_cpu = snext->tickled_cpu;
         d.skipped = *skipped;
         __trace_var(TRC_CSCHED2_RUNQ_CANDIDATE, 1,


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  parent reply	other threads:[~2017-01-26  0:30 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-26  0:29 [PATCH 0/9] xen: credit2: improve style, and tracing; fix two bugs Dario Faggioli
2017-01-26  0:29 ` [PATCH 1/9] xen: credit2: improve comments' style and definition of CSFLAG-s Dario Faggioli
2017-01-26  0:30 ` [PATCH 2/9] xen: credit2: make accessor helpers inline functions instead of macros Dario Faggioli
2017-01-26  0:30 ` [PATCH 3/9] xen: credit2: tidy up functions names by removing leading '__' Dario Faggioli
2017-01-26  0:30 ` [PATCH 4/9] xen: credit2: group the runq manipulating functions Dario Faggioli
2017-01-26  0:30 ` [PATCH 5/9] xen: credit2: always mark a tickled pCPU as... tickled! Dario Faggioli
2017-01-26  0:30 ` [PATCH 6/9] xen: credit2: don't miss accounting while doing a credit reset Dario Faggioli
2017-01-26  0:30 ` [PATCH 7/9] xen/tools: tracing: credits can go negative, so use int Dario Faggioli
2017-01-26  0:30 ` Dario Faggioli [this message]
2017-01-26  0:30 ` [PATCH 9/9] xen/tools: tracing: always report how long next slice will be Dario Faggioli

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