Juhana Sadeharju wrote:
>
> Now the latency jumped from 2.3 ms to 7 ms
7 ms was when starting the X server.
With "typical workloads" I'm currently showing the following latency
distribution:
0-1 msec 99.994%
1-2 msec 0.003%
2-3 msec 0.002%
4-5 msec 0.001%
This is with the previously-posted six conditional_schedule()s and a
kinder, gentler zap_page_range().
Progress is currently bogged down chasing irrelevant bogosity in the
memory manager. Unless magic happens I'll shelve that and get something
less ambitious out.
But audio guys, please comprehend this: there is _no point_ in
submitting this work for inclusion unless you can stand in front of
Linus with your hands on your hearts and say "This works for us".
I am quite mystified as to why you're putting so much effort into joint
letters and such, and so little into testing a purported solution. I've
had two emails which said "cool for me", an apology from Paul B-D who is
travelling and that's all.
For your convenience I have attached here Saturday's patch against
2.4.0-test3-pre4. Go compile.
--- linux-2.4.0-test3-pre4/mm/filemap.c Thu Jul 6 20:23:47 2000
+++ linux-akpm/mm/filemap.c Sat Jul 8 14:33:54 2000
@@ -160,6 +160,7 @@
start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
repeat:
+ conditional_schedule(); /* sys_unlink() */
head = &mapping->pages;
spin_lock(&pagecache_lock);
curr = head->next;
@@ -450,6 +451,7 @@
page_cache_get(page);
spin_unlock(&pagecache_lock);
+ conditional_schedule(); /* sys_sync() */
lock_page(page);
/* The buffers could have been free'd while we waited for the page lock */
@@ -1081,6 +1083,8 @@
* "pos" here (the actor routine has to update the user buffer
* pointers and the remaining count).
*/
+ conditional_schedule(); /* sys_read() */
+
nr = actor(desc, page, offset, nr);
offset += nr;
index += offset >> PAGE_CACHE_SHIFT;
@@ -1533,6 +1537,7 @@
* vma/file is guaranteed to exist in the unmap/sync cases because
* mmap_sem is held.
*/
+ conditional_schedule(); /* sys_msync() */
return page->mapping->a_ops->writepage(file, page);
}
@@ -2486,6 +2491,8 @@
while (count) {
unsigned long bytes, index, offset;
char *kaddr;
+
+ conditional_schedule(); /* sys_write() */
/*
* Try to find the page in the cache. If it isn't there,
--- linux-2.4.0-test3-pre4/fs/buffer.c Thu Jul 6 20:23:47 2000
+++ linux-akpm/fs/buffer.c Sat Jul 8 14:34:08 2000
@@ -2123,6 +2123,7 @@
__wait_on_buffer(p);
} else if (buffer_dirty(p))
ll_rw_block(WRITE, 1, &p);
+ conditional_schedule(); /* sys_msync() */
} while (tmp != bh);
}
--- linux-2.4.0-test3-pre4/include/linux/sched.h Thu Jul 6 20:23:47 2000
+++ linux-akpm/include/linux/sched.h Sat Jul 8 15:15:03 2000
@@ -146,6 +146,8 @@
extern signed long FASTCALL(schedule_timeout(signed long timeout));
asmlinkage void schedule(void);
+#define conditional_schedule() do { if (current->need_resched) schedule(); } while (0)
+
/*
* The default fd array needs to be at least BITS_PER_LONG,
* as this is the granularity returned by copy_fdset().
@@ -348,6 +350,8 @@
u32 self_exec_id;
/* Protection of (de-)allocation: mm, files, fs, tty */
spinlock_t alloc_lock;
+
+ int curr_syscall;
};
/*
@@ -423,6 +427,7 @@
blocked: {{0}}, \
sigqueue: NULL, \
sigqueue_tail: &tsk.sigqueue, \
+ curr_syscall: 0, \
alloc_lock: SPIN_LOCK_UNLOCKED \
}
-
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This archive was generated by hypermail 2b29 : Sat Jul 15 2000 - 21:00:12 EST