Re: [BUG] /proc/pid/stat access stalls badly for swapping process,2.4.0-test10
In article [EMAIL PROTECTED], Mike Galbraith [EMAIL PROTECTED] wrote: (This schenario, btw, is much harder to trigger on SMP than on UP. And it's completely separate from the issue of simple disk bandwidth issues which can obviously cause no end of stalls on anything that needs the disk, and which can also happen on SMP). Unfortunately, it didn't help in the scenario I'm running. time make -j30 bzImage: real14m19.987s (within stock variance) user6m24.480s sys 1m12.970s Note that the above kin of "throughput performance" should not have been affected, and was not what I was worried about. procs memoryswap io system cpu r b w swpd free buff cache si sobibo incs us sy id 31 2 1 12 1432 4440 12660 0 1227 151 202 848 89 11 0 34 4 1 1908 2584536 5376 248 1904 602 763 785 4094 63 32 5 13 19 1 64140 67728604 33784 106500 84612 43625 21683 19080 52168 28 22 50 Looks like there was a big delay in vmstat there - that could easily be due to simple disk throughput issues.. Does it feel any different under the original load that got the original complaint? The patch may have just been buggy and ineffective, for all I know. Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [BUG] /proc/pid/stat access stalls badly for swapping process,2.4.0-test10
Linus Torvalds wrote: ... And it has everything to do with the fact that the way Linux semaphores are implemented, a non-blocking process has a HUGE advantage over a blocking one. Linux kernel semaphores are extreme unfair in that way. ... The original running process comes back faulting again, finds the semaphore still unlocked (the "ps" process is awake but has not gotten to run yet), gets the semaphore, and falls asleep on the IO for the next page. The "ps" process actually gets to run now, but it's a bit late. The semaphore is locked again. Repeat until luck breaks the bad circle. But doesn't __down have a fast path coded in assembly? In other words, it only hits your patched code if there is already contention, which there isn't in this case, and therefore the bug...? David Mansfield - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [BUG] /proc/pid/stat access stalls badly for swapping process,2.4.0-test10
In article [EMAIL PROTECTED], David Mansfield [EMAIL PROTECTED] wrote: Linus Torvalds wrote: ... And it has everything to do with the fact that the way Linux semaphores are implemented, a non-blocking process has a HUGE advantage over a blocking one. Linux kernel semaphores are extreme unfair in that way. ... The original running process comes back faulting again, finds the semaphore still unlocked (the "ps" process is awake but has not gotten to run yet), gets the semaphore, and falls asleep on the IO for the next page. The "ps" process actually gets to run now, but it's a bit late. The semaphore is locked again. Repeat until luck breaks the bad circle. But doesn't __down have a fast path coded in assembly? In other words, it only hits your patched code if there is already contention, which there isn't in this case, and therefore the bug...? The __down() case should be hit if there's a waiter, even if that waiter has not yet been able to pick up the lock (the waiter _will_ have decremented the count to negative in order to trigger the proper logic at release time). But as I mentioned, the pseudo-patch was certainly untested, so somebody should probably walk through the cases to check that I didn't miss something. Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [BUG] /proc/pid/stat access stalls badly for swapping process,2.4.0-test10
As to the real reason for stalls on /proc/pid/stat, I bet it has nothing
to do with IO except indirectly (the IO is necessary to trigger the
problem, but the _reason_ for the problem lies elsewhere).
And it has everything to do with the fact that the way Linux semaphores
are implemented, a non-blocking process has a HUGE advantage over a
blocking one. Linux kernel semaphores are extreme unfair in that way.
What happens is that some process is getting a lot of VM faults and gets
its VM semaphore. No contention yet. it holds the semaphore over the
IO, and now another process does a "ps".
The "ps" process goes to sleep on the semaphore. So far so good.
The original process releases the semaphore, which increments the count,
and wakes up the process waiting for it. Note that it _wakes_ it, it does
not give the semaphore to it. Big difference.
The process that got woken up will run eventually. Probably not all that
immediately, because the process that woke it (and held the semaphore)
just slept on a page fault too, so it's not likely to immediately
relinquish the CPU.
The original running process comes back faulting again, finds the
semaphore still unlocked (the "ps" process is awake but has not gotten to
run yet), gets the semaphore, and falls asleep on the IO for the next
page.
The "ps" process actually gets to run now, but it's a bit late. The
semaphore is locked again.
Repeat until luck breaks the bad circle.
(This schenario, btw, is much harder to trigger on SMP than on UP. And
it's completely separate from the issue of simple disk bandwidth issues
which can obviously cause no end of stalls on anything that needs the
disk, and which can also happen on SMP).
NOTE! If somebody wants to fix this, the fix should be reasonably simple
but needs to be quite exhaustively checked and double-checked. It's just
too easy to break the semaphores by mistake.
The way to make semaphores more fair is to NOT allow a new process to just
come in immediately and steal the semaphore in __down() if there are other
sleepers. This is most easily accomplished by something along the lines of
the following in __down() in arch/i386/kernel/semaphore.c
spin_lock_irq(semaphore_lock);
sem-sleepers++;
+
+ /*
+* Are there other people waiting for this?
+* They get to go first.
+*/
+ if (sleepers 1)
+ goto inside;
for (;;) {
int sleepers = sem-sleepers;
/*
* Add "everybody else" into it. They aren't
* playing, because we own the spinlock.
*/
if (!atomic_add_negative(sleepers - 1, sem-count)) {
sem-sleepers = 0;
break;
}
sem-sleepers = 1; /* us - see -1 above */
+inside:
spin_unlock_irq(semaphore_lock);
schedule();
tsk-state = TASK_UNINTERRUPTIBLE|TASK_EXCLUSIVE;
spin_lock_irq(semaphore_lock);
}
spin_unlock_irq(semaphore_lock);
But note that teh above is UNTESTED and also note that from a throughput
(as opposed to latency) standpoint being unfair tends to be nice.
Anybody want to try out something like the above? (And no, I'm not
applying it to my tree yet. It needs about a hundred pairs of eyes to
verify that there isn't some subtle "lost wakeup" race somewhere).
Linus
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Re: [BUG] /proc/pid/stat access stalls badly for swapping process,2.4.0-test10
On Thu, 9 Nov 2000, Linus Torvalds wrote: As to the real reason for stalls on /proc/pid/stat, I bet it has nothing to do with IO except indirectly (the IO is necessary to trigger the problem, but the _reason_ for the problem lies elsewhere). And it has everything to do with the fact that the way Linux semaphores are implemented, a non-blocking process has a HUGE advantage over a blocking one. Linux kernel semaphores are extreme unfair in that way. What happens is that some process is getting a lot of VM faults and gets its VM semaphore. No contention yet. it holds the semaphore over the IO, and now another process does a "ps". The "ps" process goes to sleep on the semaphore. So far so good. The original process releases the semaphore, which increments the count, and wakes up the process waiting for it. Note that it _wakes_ it, it does not give the semaphore to it. Big difference. The process that got woken up will run eventually. Probably not all that immediately, because the process that woke it (and held the semaphore) just slept on a page fault too, so it's not likely to immediately relinquish the CPU. The original running process comes back faulting again, finds the semaphore still unlocked (the "ps" process is awake but has not gotten to run yet), gets the semaphore, and falls asleep on the IO for the next page. The "ps" process actually gets to run now, but it's a bit late. The semaphore is locked again. Repeat until luck breaks the bad circle. (This schenario, btw, is much harder to trigger on SMP than on UP. And it's completely separate from the issue of simple disk bandwidth issues which can obviously cause no end of stalls on anything that needs the disk, and which can also happen on SMP). Unfortunately, it didn't help in the scenario I'm running. time make -j30 bzImage: real14m19.987s (within stock variance) user6m24.480s sys 1m12.970s procs memoryswap io system cpu r b w swpd free buff cache si sobibo incs us sy id 31 2 1 12 1432 4440 12660 0 1227 151 202 848 89 11 0 34 4 1 1908 2584536 5376 248 1904 602 763 785 4094 63 32 5 13 19 1 64140 67728604 33784 106500 84612 43625 21683 19080 52168 28 22 50 I understood the above well enough to be very interested in seeing what happens with flush IO restricted. -Mike [try_to_free_pages()-swap_out()/shm_swap().. can fight over who gets to shrink the best candidate's footprint?] Thanks! - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [BUG] /proc/pid/stat access stalls badly for swapping process, 2.4.0-test10
On Fri, Nov 03 2000, Mike Galbraith wrote:
I very much agree. Kflushd is still hungry for free write
bandwidth here.
In the LKML tradition of code talks and silly opinions walk...
Attached is a diagnostic patch which gets kflushd under control,
and takes make -j30 bzImage build times down from 12 minutes to
9 here. I have no more massive context switching on write, and
copies seem to go a lot quicker to boot. (that may be because
some of my failures were really _really_ horrible)
Comments are very welcome. I haven't had problems with this yet,
but it's early so... This patch isn't supposed to be pretty either
(hw techs don't do pretty;) it's only supposed to say 'Huston...'
so be sure to grab a barfbag before you take a look.
Super, looks pretty good from here. I'll give it a go when I get back.
In addition, here's a small patch that disables the read stealing
of requests from the write list -- does that improve behaviour
when we are busy flushing?
--
* Jens Axboe [EMAIL PROTECTED]
* SuSE Labs
--- drivers/block/ll_rw_blk.c~ Fri Nov 3 03:22:25 2000
+++ drivers/block/ll_rw_blk.c Fri Nov 3 03:23:24 2000
@@ -455,35 +455,17 @@
struct list_head *list = q-request_freelist[rw];
struct request *rq;
- /*
-* Reads get preferential treatment and are allowed to steal
-* from the write free list if necessary.
-*/
if (!list_empty(list)) {
rq = blkdev_free_rq(list);
- goto got_rq;
- }
-
- /*
-* if the WRITE list is non-empty, we know that rw is READ
-* and that the READ list is empty. allow reads to 'steal'
-* from the WRITE list.
-*/
- if (!list_empty(q-request_freelist[WRITE])) {
- list = q-request_freelist[WRITE];
- rq = blkdev_free_rq(list);
- goto got_rq;
+ list_del(rq-table);
+ rq-free_list = list;
+ rq-rq_status = RQ_ACTIVE;
+ rq-special = NULL;
+ rq-q = q;
+ return rq;
}
return NULL;
-
-got_rq:
- list_del(rq-table);
- rq-free_list = list;
- rq-rq_status = RQ_ACTIVE;
- rq-special = NULL;
- rq-q = q;
- return rq;
}
/*
Re: [BUG] /proc/pid/stat access stalls badly for swapping process,2.4.0-test10
On Fri, 3 Nov 2000, Jens Axboe wrote: On Fri, Nov 03 2000, Mike Galbraith wrote: I very much agree. Kflushd is still hungry for free write bandwidth here. In the LKML tradition of code talks and silly opinions walk... Attached is a diagnostic patch which gets kflushd under control, and takes make -j30 bzImage build times down from 12 minutes to 9 here. I have no more massive context switching on write, and copies seem to go a lot quicker to boot. (that may be because some of my failures were really _really_ horrible) Comments are very welcome. I haven't had problems with this yet, but it's early so... This patch isn't supposed to be pretty either (hw techs don't do pretty;) it's only supposed to say 'Huston...' so be sure to grab a barfbag before you take a look. Super, looks pretty good from here. I'll give it a go when I get back. In addition, here's a small patch that disables the read stealing of requests from the write list -- does that improve behaviour when we are busy flushing? Yes. I've done this a bit differently here, and have had good results. I only disable stealing when I need flush throughput. Now that the box isn't biting off more than it can chew quite as often, I'll try this again. I'm pretty darn sure that I can get more throughput, but : I've learned that getting too much can do really OOGLY things. (turns box into single user single tasking streaming IO monster from hell) -Mike - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [BUG] /proc/pid/stat access stalls badly for swapping process, 2.4.0-test10
Hi Rik, I can probably give some more datapoints. Here is the console output of my test machine (there is a 'vmstat 5' running in background): [root@ls3016 /root]# killall shmtst [root@ls3016 /root]# 1 12 2 0 1607668 18932 2110496 0 0 67154 1115842 1050063 2029389 0 2 98 0 10 2 0 1607564 18932 2110496 0 0 0 300 317 426 0 0 100 0 10 2 0 1607408 18932 2110496 0 0 0 301 336 473 0 0 100 0 10 2 0 1607560 18932 2110508 0 0 0 307 318 430 0 0 100 0 10 2 0 1607556 18932 2110512 0 0 0 304 324 433 0 0 100 0 10 2 0 1607528 18932 2110512 0 0 0 272 308 410 0 1 99 0 10 2 0 1607440 18932 2110516 0 0 0 315 323 438 0 1 99 0 10 2 0 1607528 18932 2110516 0 0 0 323 316 424 0 0 100 0 10 2 0 1607556 18932 2110516 0 0 0 304 309 410 0 0 100 0 10 2 0 1607600 18932 2110528 0 0 0 298 314 418 0 0 100 0 10 2 0 1607384 18932 2110528 0 0 0 296 307 406 0 1 99 0 10 2 0 1607284 18932 2110528 0 0 0 304 315 421 0 0 100 0 10 2 0 1607668 18932 2110528 0 0 0 298 304 402 0 0 100 0 10 2 0 1607576 18932 2110528 0 0 0 285 307 405 0 0 100 0 10 2 0 1607656 18932 2110528 0 0 0 292 303 399 0 1 99 0 10 2 0 1607928 18932 2110528 0 0 0 313 310 408 0 0 100 procs memoryswap io system cpu r b w swpd free buff cache si sobibo incs us sy id 0 10 2 0 1608440 18932 2110528 0 0 0 340 313 417 0 1 99 0 10 2 0 1608260 18932 2110528 0 0 0 298 318 426 0 0 100 0 10 2 0 1608208 18932 2110528 0 0 0 314 334 448 0 1 99 0 10 2 0 1608396 18932 2110528 0 0 0 323 316 421 0 1 99 0 10 2 0 1608204 18932 2110548 0 0 0 334 333 458 0 0 100 0 10 2 0 1607888 18932 2110580 0 0 0 336 329 448 0 1 99 0 10 2 0 1608040 18932 2110584 0 0 0 317 321 435 0 0 100 0 10 2 0 1608032 18932 2110588 0 0 0 241 318 425 0 0 100 0 10 2 0 1608028 18932 2110592 0 0 0 257 325 443 0 1 99 0 10 3 0 1608028 18932 2110592 0 0 0 258 323 435 0 0 99 0 10 2 0 1608032 18932 2110592 0 0 0 241 316 425 0 0 100 0 10 2 0 1608024 18932 2110592 0 0 0 261 337 460 0 0 100 0 10 2 0 1608016 18932 2110592 0 0 0 253 328 444 0 0 100 0 10 2 0 1608024 18932 2110592 0 0 0 252 320 435 0 0 100 0 10 2 0 1608012 18932 2110592 0 0 0 255 326 446 0 0 100 0 10 2 0 1608020 18932 2110592 0 0 0 255 326 444 0 1 99 0 10 2 0 1608012 18932 2110600 0 0 0 261 341 469 0 0 100 0 10 2 0 1607992 18932 2110608 0 0 0 261 344 479 0 0 100 0 10 2 0 1607992 18932 2110612 0 0 0 264 342 471 0 0 100 0 10 2 0 1607984 18932 2110612 0 0 0 266 334 462 0 0 100 0 10 2 0 1607980 18932 2110620 0 0 0 273 340 468 0 0 99 procs memoryswap io system cpu r b w swpd free buff cache si sobibo incs us sy id 0 10 2 0 1607972 18932 2110624 0 0 0 266 345 474 0 1 99 0 10 2 0 1607940 18932 2110640 0 0 0 256 341 462 0 0 100 0 10 2 0 1607936 18932 2110644 0 0 0 262 339 462 0 1 99 0 10 2 0 1607940 18932 2110644 0 0 0 261 333 450 0 1 99 0 10 2 0 1607944 18932 2110644 0 0 0 253 335 454 0 0 100 0 10 2 0 1607944 18932 2110644 0 0 0 272 352 479 0 1 99 [root@ls3016 /root]# ps l F UID PID PPID PRI NI VSZ RSS WCHAN STAT TTYTIME COMMAND 100 0 820 1 9 0 2200 1168 wait4 SttyS0 0:00 login -- ro 100 0 862 820 14 0 1756 976 wait4 SttyS0 0:00 -bash 000 0 878 862 9 0 1080 360 down DttyS0 11:27 ./shmtst 10 000 0 879 862 9 0 1080 360 down DttyS0 15:21 ./shmtst 15 040 0 880 878 9 0 1092 416 wait_o DttyS0 8:55 ./shmtst 10 040 0 881 878 9 0 1080 360 down DttyS0 10:22 ./shmtst 10 444 0 882 878 9 0 00 do_exi ZttyS0 10:00 [shmtst de 040 0 883 878 9 0 1092 416 wait_o DttyS0 9:30 ./shmtst 10 040 0 884 878 9 0 1092 416 down DttyS0 8:44 ./shmtst 10 040 0 885 878 9 0 1092 416 down DttyS0 9:01 ./shmtst 10 444 0 886 878 9 0 0
Re: [BUG] /proc/pid/stat access stalls badly for swapping process, 2.4.0-test10
On Thu, Nov 02 2000, Val Henson wrote: 3) combine this with the elevator starvation stuff (ask Jens Axboe for blk-7 to alleviate this issue) and you have a scenario where processes using /proc/pid/stat have the possibility to block on multiple processes that are in the process of handling a page fault (but are being starved) I'm experimenting with blk.[67] in test10 right now. The stalls are not helped at all. It doesn't seem to become request bound (haven't instrumented that yet to be sure) but the stalls persist. -Mike This is not an elevator starvation problem. True, but the blk-xx patches help work-around (what I believe) is bad flushing behaviour by the vm. I also experienced these stalls with my IDE-only system. Unless I'm badly mistaken, the elevator is only used on SCSI disks, therefore elevator starvation cannot be blamed for this problem. These stalls are particularly annoying since I want to find the pid of the process hogging memory in order to kill it, but the read from /proc stalls for 45 seconds or more. You are badly mistaken. -- * Jens Axboe [EMAIL PROTECTED] * SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [BUG] /proc/pid/stat access stalls badly for swapping process,2.4.0-test10
On Thu, 2 Nov 2000, Jens Axboe wrote: On Thu, Nov 02 2000, Val Henson wrote: 3) combine this with the elevator starvation stuff (ask Jens Axboe for blk-7 to alleviate this issue) and you have a scenario where processes using /proc/pid/stat have the possibility to block on multiple processes that are in the process of handling a page fault (but are being starved) I'm experimenting with blk.[67] in test10 right now. The stalls are not helped at all. It doesn't seem to become request bound (haven't instrumented that yet to be sure) but the stalls persist. -Mike This is not an elevator starvation problem. True, but the blk-xx patches help work-around (what I believe) is bad flushing behaviour by the vm. I very much agree. Kflushd is still hungry for free write bandwidth here. Of course it's _going_ to have to wait if you're doing max IO throughput, but when you're flushing, you need to let kflushd have the bandwidth it needs to do it's job. I don't think it's getting what it needs, and am trying two things. 1. Revoke read's ability to steal requests while we're in a heavy flushing situation. Flushing must proceed, and it must go at full speed. (Actually, reversing the favoritism when you need flush bandwidth makes sense to me, and does help if limited.. if not limited, it hurts like hell) 2. Use the information that we are starving (or going full bore) to tell the VM to keep it's fingers off dirty buffers. If we're flushing at disk speed, page_launder() can't do anything useful with dirty buffers, it can only do harm IMHO. -Mike P.S. Before I revert to Luke Codecrawler mode, I have a wild problem theory I'd appreciate comments on.. preferably the kind where I become extremely busy thinking about their content ;-) If one __alloc_pages() is waiting for kswapd, kswapd tries to do synchronous flushing.. if the write queue is nearly (or) exausted and page_launder() couldn't clean any buffers on it's first pass, it blasts the queue some more and stalls. If kswapd, kflushd and kupdate are all waiting for a request, and then say a GFP_BUFFER allocation comes along.. (we're low on memory) we do SCHED_YIELD schedule(). If we're holding IO locks, nobody can do IO. OK, if there's nobody else running, we come right back and either finish the allocation of fail. But, if you have other allocations trying to flush buffers (GFP_KERNEL eg), they are not only in danger of stacking up due to a request shortage, but they can't get whatever IO locks the GFP_BUFFER allocation is holding anyway so are doomed until we do schedule back to the GFP_BUFFER allocating task. Isn't scheduling while holding IO locks the wrong thing to do? It's protected from neither GFP_BUFFER nor PF_MEMALLOC. I must be missing something.. but what? ears at maximum gain - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [BUG] /proc/pid/stat access stalls badly for swapping process, 2.4.0-test10
On Wed, 1 Nov 2000, David Mansfield wrote: I'd like to report what seems like a performance problem in the latest kernels. Actually, all recent kernels have exhibited this problem, but I was waiting for the new VM stuff to stabilize before reporting it. My test is: run 7 processes that each allocate and randomly access 32mb of ram (on a 256mb machine). Even though 7*32MB = 224MB, this still sends the machine lightly into swap. The machine continues to function fairly smoothly for the most part. I can do filesystem operations, run new programs, move desktops in X etc. Except: programs which access /proc/pid/stat stall for an inderminate amount of time. For example, 'ps' and 'vmstat' stall BADLY in these scenarios. I have had the stalls last over a minute in higher VM pressure situations. I have one possible reason for this 1) the procfs process does (in fs/proc/array.c::proc_pid_stat) down(mm-mmap_sem); 2) but, in order to do that, it has to wait until the process it is trying to stat has /finished/ its page fault, and is not into its next one ... 3) combine this with the elevator starvation stuff (ask Jens Axboe for blk-7 to alleviate this issue) and you have a scenario where processes using /proc/pid/stat have the possibility to block on multiple processes that are in the process of handling a page fault (but are being starved) regards, Rik -- "What you're running that piece of shit Gnome?!?!" -- Miguel de Icaza, UKUUG 2000 http://www.conectiva.com/ http://www.surriel.com/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [BUG] /proc/pid/stat access stalls badly for swapping process, 2.4.0-test10
On Wed, 1 Nov 2000, Rik van Riel wrote: On Wed, 1 Nov 2000, David Mansfield wrote: I'd like to report what seems like a performance problem in the latest kernels. Actually, all recent kernels have exhibited this problem, but I was waiting for the new VM stuff to stabilize before reporting it. My test is: run 7 processes that each allocate and randomly access 32mb of ram (on a 256mb machine). Even though 7*32MB = 224MB, this still sends the machine lightly into swap. The machine continues to function fairly smoothly for the most part. I can do filesystem operations, run new programs, move desktops in X etc. Except: programs which access /proc/pid/stat stall for an inderminate amount of time. For example, 'ps' and 'vmstat' stall BADLY in these scenarios. I have had the stalls last over a minute in higher VM pressure situations. I have one possible reason for this 1) the procfs process does (in fs/proc/array.c::proc_pid_stat) down(mm-mmap_sem); 2) but, in order to do that, it has to wait until the process it is trying to stat has /finished/ its page fault, and is not into its next one ... 3) combine this with the elevator starvation stuff (ask Jens Axboe for blk-7 to alleviate this issue) and you have a scenario where processes using /proc/pid/stat have the possibility to block on multiple processes that are in the process of handling a page fault (but are being starved) I'm experimenting with blk.[67] in test10 right now. The stalls are not helped at all. It doesn't seem to become request bound (haven't instrumented that yet to be sure) but the stalls persist. -Mike - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
