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authorJens Axboe <jens.axboe@oracle.com>2009-10-02 19:27:04 +0200
committerJens Axboe <jens.axboe@oracle.com>2009-10-02 20:06:02 +0200
commit1d2235152dc745c6d94bedb550fea84cffdbf768 (patch)
treeeb489f01dd6d506c1b785bae03e68e42145a055b
parentb0da3f0dada78832c9da03ad2152ae76bd9a2496 (diff)
cfq-iosched: add a knob for desktop interactiveness
This is basically identical to what Vivek Goyal posted, but combined into one and labelled 'desktop' instead of 'fairness'. The goal is to continue to improve on the latency side of things as it relates to interactiveness, keeping the questionable bits under this sysfs tunable so it would be easy for throughput-only people to turn off. Apart from adding the interactive sysfs knob, it also adds the behavioural change of allowing slice idling even if the hardware does tagged command queuing. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
-rw-r--r--block/cfq-iosched.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 1ca813b16e7..8917f2b3a78 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -173,6 +173,7 @@ struct cfq_data {
unsigned int cfq_slice[2];
unsigned int cfq_slice_async_rq;
unsigned int cfq_slice_idle;
+ unsigned int cfq_desktop;
struct list_head cic_list;
@@ -1951,7 +1952,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
enable_idle = old_idle = cfq_cfqq_idle_window(cfqq);
if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
- (cfqd->hw_tag && CIC_SEEKY(cic)))
+ (!cfqd->cfq_desktop && cfqd->hw_tag && CIC_SEEKY(cic)))
enable_idle = 0;
else if (sample_valid(cic->ttime_samples)) {
if (cic->ttime_mean > cfqd->cfq_slice_idle)
@@ -2480,6 +2481,7 @@ static void *cfq_init_queue(struct request_queue *q)
cfqd->cfq_slice[1] = cfq_slice_sync;
cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
cfqd->cfq_slice_idle = cfq_slice_idle;
+ cfqd->cfq_desktop = 1;
cfqd->hw_tag = 1;
return cfqd;
@@ -2549,6 +2551,7 @@ SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1);
SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1);
SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1);
SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
+SHOW_FUNCTION(cfq_desktop_show, cfqd->cfq_desktop, 0);
#undef SHOW_FUNCTION
#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
@@ -2580,6 +2583,7 @@ STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1);
STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1);
STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1,
UINT_MAX, 0);
+STORE_FUNCTION(cfq_desktop_store, &cfqd->cfq_desktop, 0, 1, 0);
#undef STORE_FUNCTION
#define CFQ_ATTR(name) \
@@ -2595,6 +2599,7 @@ static struct elv_fs_entry cfq_attrs[] = {
CFQ_ATTR(slice_async),
CFQ_ATTR(slice_async_rq),
CFQ_ATTR(slice_idle),
+ CFQ_ATTR(desktop),
__ATTR_NULL
};