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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 4/6] xen: credit2: rearrange members of control structures
With the aim of improving memory size and layout, and
at the same time trying to put related fields reside
in the same cacheline.
Here's a summary of the output of `pahole`, with and
without this patch, for the affected data structures.
csched2_runqueue_data:
* Before:
size: 216, cachelines: 4, members: 14
sum members: 208, holes: 2, sum holes: 8
last cacheline: 24 bytes
* After:
size: 208, cachelines: 4, members: 14
last cacheline: 16 bytes
csched2_private:
* Before:
size: 120, cachelines: 2, members: 8
sum members: 112, holes: 1, sum holes: 4
padding: 4
last cacheline: 56 bytes
* After:
size: 112, cachelines: 2, members: 8
last cacheline: 48 bytes
csched2_vcpu:
* Before:
size: 112, cachelines: 2, members: 14
sum members: 108, holes: 1, sum holes: 4
last cacheline: 48 bytes
* After:
size: 112, cachelines: 2, members: 14
padding: 4
last cacheline: 48 bytes
While there, improve the wording, style and alignment
of comments too.
Signed-off-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
---
Cc: George Dunlap <george.dunlap@xxxxxxxxxx>
Cc: Anshul Makkar <anshulmakkar@xxxxxxxxx>
---
xen/common/sched_credit2.c | 102 ++++++++++++++++++++++----------------------
1 file changed, 51 insertions(+), 51 deletions(-)
diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index 15862f2..9814072 100644
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -355,40 +355,41 @@ custom_param("credit2_runqueue", parse_credit2_runqueue);
* Per-runqueue data
*/
struct csched2_runqueue_data {
- int id;
-
- spinlock_t lock; /* Lock for this runqueue. */
- cpumask_t active; /* CPUs enabled for this runqueue */
-
- struct list_head runq; /* Ordered list of runnable vms */
- struct list_head svc; /* List of all vcpus assigned to this runqueue */
- unsigned int max_weight;
- unsigned int pick_bias;/* Last CPU we picked. Start from it next time */
-
- cpumask_t idle, /* Currently idle pcpus */
- smt_idle, /* Fully idle-and-untickled cores (see below) */
- tickled; /* Have been asked to go through schedule */
- int load; /* Instantaneous load: Length of queue + num
non-idle threads */
- s_time_t load_last_update; /* Last time average was updated */
- s_time_t avgload; /* Decaying queue load */
- s_time_t b_avgload; /* Decaying queue load modified by balancing */
+ spinlock_t lock; /* Lock for this runqueue */
+
+ struct list_head runq; /* Ordered list of runnable vms */
+ int id; /* ID of this runqueue (-1 if invalid) */
+
+ int load; /* Instantaneous load (num of non-idle vcpus) */
+ s_time_t load_last_update; /* Last time average was updated */
+ s_time_t avgload; /* Decaying queue load */
+ s_time_t b_avgload; /* Decaying queue load modified by balancing */
+
+ cpumask_t active, /* CPUs enabled for this runqueue */
+ smt_idle, /* Fully idle-and-untickled cores (see below) */
+ tickled, /* Have been asked to go through schedule */
+ idle; /* Currently idle pcpus */
+
+ struct list_head svc; /* List of all vcpus assigned to the runqueue */
+ unsigned int max_weight; /* Max weight of the vcpus in this runqueue */
+ unsigned int pick_bias; /* Last picked pcpu. Start from it next time */
};
/*
* System-wide private data
*/
struct csched2_private {
- rwlock_t lock;
- cpumask_t initialized; /* CPU is initialized for this pool */
-
- struct list_head sdom; /* Used mostly for dump keyhandler. */
+ rwlock_t lock; /* Private scheduler lock */
- cpumask_t active_queues; /* Queues which may have active cpus */
- struct csched2_runqueue_data *rqd;
+ unsigned int load_precision_shift; /* Precision of load calculations */
+ unsigned int load_window_shift; /* Lenght of load decaying window */
+ unsigned int ratelimit_us; /* Rate limiting for this scheduler */
+
+ cpumask_t active_queues; /* Runqueues with (maybe) active cpus */
+ struct csched2_runqueue_data *rqd; /* Data of the various runqueues */
- unsigned int load_precision_shift;
- unsigned int load_window_shift;
- unsigned ratelimit_us; /* each cpupool can have its own ratelimit */
+ cpumask_t initialized; /* CPUs part of this scheduler */
+ struct list_head sdom; /* List of domains (for debug key) */
};
/*
@@ -403,37 +404,36 @@ static DEFINE_PER_CPU(int, runq_map);
* Virtual CPU
*/
struct csched2_vcpu {
- struct list_head rqd_elem; /* On the runqueue data list */
- struct list_head runq_elem; /* On the runqueue */
- struct csched2_runqueue_data *rqd; /* Up-pointer to the runqueue */
-
- /* Up-pointers */
- struct csched2_dom *sdom;
- struct vcpu *vcpu;
-
- unsigned int weight;
- unsigned int residual;
-
- int credit;
- s_time_t start_time; /* When we were scheduled (used for credit) */
- unsigned flags; /* 16 bits doesn't seem to play well with clear_bit()
*/
- int tickled_cpu; /* cpu tickled for picking us up (-1 if none) */
-
- /* Individual contribution to load */
- s_time_t load_last_update; /* Last time average was updated */
- s_time_t avgload; /* Decaying queue load */
-
- struct csched2_runqueue_data *migrate_rqd; /* Pre-determined rqd to which
to migrate */
+ struct list_head rqd_elem; /* On csched2_runqueue_data's svc list
*/
+ struct csched2_runqueue_data *rqd; /* Up-pointer to the runqueue
*/
+
+ int credit; /* Current amount of credit
*/
+ unsigned int weight; /* Weight of this vcpu
*/
+ unsigned int residual; /* Reminder of div(max_weight/weight)
*/
+ unsigned flags; /* Status flags (16 bits would be ok,
*/
+ /* but clear_bit() does not like that)
*/
+ s_time_t start_time; /* Time we were scheduled (for credit)
*/
+
+ /* Individual contribution to load
*/
+ s_time_t load_last_update; /* Last time average was updated
*/
+ s_time_t avgload; /* Decaying queue load
*/
+
+ struct list_head runq_elem; /* On the runqueue (rqd->runq)
*/
+ struct csched2_dom *sdom; /* Up-pointer to domain
*/
+ struct vcpu *vcpu; /* Up-pointer, to vcpu
*/
+
+ struct csched2_runqueue_data *migrate_rqd; /* Pre-determined migr. target
*/
+ int tickled_cpu; /* Cpu that will pick us (-1 if none)
*/
};
/*
* Domain
*/
struct csched2_dom {
- struct list_head sdom_elem;
- struct domain *dom;
- uint16_t weight;
- uint16_t nr_vcpus;
+ struct list_head sdom_elem; /* On csched2_runqueue_data's sdom list
*/
+ struct domain *dom; /* Up-pointer to domain
*/
+ uint16_t weight; /* User specified weight
*/
+ uint16_t nr_vcpus; /* Number of vcpus of this domain
*/
};
/*
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