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mm/iob: Add a divider that can be used to reduce the rate of IOB notifications.

This commit is contained in:
Gregory Nutt 2018-09-13 06:53:58 -06:00
parent 57e5142b98
commit 22da175629
2 changed files with 41 additions and 1 deletions
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14
mm/iob/Kconfig
View File

@ -71,6 +71,20 @@ config IOB_NOTIFIER
support poll() logic where the poll must wait for an IOB to become
available.
config IOB_NOTIFIER_DIV
int "Notification divider"
default 4
range 1 64
depends on IOB_NOTIFIER
---help---
IOBs may become available at very high rates and the resulting
notification processing can be substantial even if there is nothing
waiting for a free IOB. This divider will reduce that rate of
notification. This must be an even power of two. Supported values
include: 1, 2, 4, 8, 16, 32, 64. The default value of 4 means that
a notification will be sent only when there are a multiple of 4 IOBs
available.
config IOB_DEBUG
bool "Force I/O buffer debug"
default n

28
mm/iob/iob_free.c
View File

@ -50,6 +50,28 @@
#include "iob.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#if !defined(CONFIG_IOB_NOTIFIER_DIV) || CONFIG_IOB_NOTIFIER_DIV < 2
# define IOB_DIVIDER 1
#elif CONFIG_IOB_NOTIFIER_DIV < 4
# define IOB_DIVIDER 2
#elif CONFIG_IOB_NOTIFIER_DIV < 8
# define IOB_DIVIDER 4
#elif CONFIG_IOB_NOTIFIER_DIV < 16
# define IOB_DIVIDER 8
#elif CONFIG_IOB_NOTIFIER_DIV < 32
# define IOB_DIVIDER 16
#elif CONFIG_IOB_NOTIFIER_DIV < 64
# define IOB_DIVIDER 32
#else
# define IOB_DIVIDER 64
#endif
#define IOB_MASK (IOB_DIVIDER - 1)
/****************************************************************************
* Public Functions
****************************************************************************/
@ -67,6 +89,9 @@ FAR struct iob_s *iob_free(FAR struct iob_s *iob)
{
FAR struct iob_s *next = iob->io_flink;
irqstate_t flags;
#ifdef CONFIG_IOB_NOTIFIER
int16_t navail;
#endif
iobinfo("iob=%p io_pktlen=%u io_len=%u next=%p\n",
iob, iob->io_pktlen, iob->io_len, next);
@ -149,7 +174,8 @@ FAR struct iob_s *iob_free(FAR struct iob_s *iob)
* for an IOB.
*/
if (iob_navail(false) > 0)
navail = iob_navail(false);
if (navail > 0 && (navail & IOB_MASK) == 0)
{
/* Signal any threads that have requested a signal notification
* when an IOB becomes available.