Re: Linux-2.4.1-pre11 / ll_rw_b watermark metric?
On Mon, Jan 29 2001, Petr Vandrovec wrote: > On 29 Jan 01 at 4:43, Dieter Nützel wrote: > > I have pre11 running with Andrea's suggested fix. > > > > high_queued_sectors = total_ram / 3; > > low_queued_sectors = high_queued_sectors / 2; > > if (low_queued_sectors < 0) > > low_queued_sectors = total_ram / 2; > > > > I have one question: How it can happen that low_queued_sectors > is less than zero with this changed logic? (And if it get triggered, > low_queued_sectors will be greater than high_queued_sectors - which > is not what we want...) This wasn't my change, but you're right it's wrong. > But it is certainly better than 2.4.0-pre8 approach, as > with 200MB of memory (exactly 192MB left unused) you can end up with > low_queued_sectors == 0... And it does not give you optimal behavior. Same here, definitely not right either. Dunno how I missed that. -- Jens Axboe - 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: Linux-2.4.1-pre11 / ll_rw_b watermark metric?
On 29 Jan 01 at 4:43, Dieter Nützel wrote: > I have pre11 running with Andrea's suggested fix. > > high_queued_sectors = total_ram / 3; > low_queued_sectors = high_queued_sectors / 2; > if (low_queued_sectors < 0) > low_queued_sectors = total_ram / 2; > I have one question: How it can happen that low_queued_sectors is less than zero with this changed logic? (And if it get triggered, low_queued_sectors will be greater than high_queued_sectors - which is not what we want...) But it is certainly better than 2.4.0-pre8 approach, as with 200MB of memory (exactly 192MB left unused) you can end up with low_queued_sectors == 0... And it does not give you optimal behavior. Best regards, Petr Vandrovec [EMAIL PROTECTED] - 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: Linux-2.4.1-pre11 / ll_rw_b watermark metric?
On 29 Jan 01 at 4:43, Dieter Ntzel wrote: I have pre11 running with Andrea's suggested fix. high_queued_sectors = total_ram / 3; low_queued_sectors = high_queued_sectors / 2; if (low_queued_sectors 0) low_queued_sectors = total_ram / 2; I have one question: How it can happen that low_queued_sectors is less than zero with this changed logic? (And if it get triggered, low_queued_sectors will be greater than high_queued_sectors - which is not what we want...) But it is certainly better than 2.4.0-pre8 approach, as with 200MB of memory (exactly 192MB left unused) you can end up with low_queued_sectors == 0... And it does not give you optimal behavior. Best regards, Petr Vandrovec [EMAIL PROTECTED] - 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: Linux-2.4.1-pre11 / ll_rw_b watermark metric?
On Mon, Jan 29 2001, Petr Vandrovec wrote: On 29 Jan 01 at 4:43, Dieter Ntzel wrote: I have pre11 running with Andrea's suggested fix. high_queued_sectors = total_ram / 3; low_queued_sectors = high_queued_sectors / 2; if (low_queued_sectors 0) low_queued_sectors = total_ram / 2; I have one question: How it can happen that low_queued_sectors is less than zero with this changed logic? (And if it get triggered, low_queued_sectors will be greater than high_queued_sectors - which is not what we want...) This wasn't my change, but you're right it's wrong. But it is certainly better than 2.4.0-pre8 approach, as with 200MB of memory (exactly 192MB left unused) you can end up with low_queued_sectors == 0... And it does not give you optimal behavior. Same here, definitely not right either. Dunno how I missed that. -- Jens Axboe - 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: Linux-2.4.1-pre11 / ll_rw_b watermark metric?
Am Montag, 29. Januar 2001 04:46 schrieb Jens Axboe:
> On Mon, Jan 29 2001, Dieter Nützel wrote:
> > I have pre11 running with Andrea's suggested fix.
> >
> > high_queued_sectors = total_ram / 3;
> > low_queued_sectors = high_queued_sectors / 2;
> > if (low_queued_sectors < 0)
> > low_queued_sectors = total_ram / 2;
> >
> > /*
> > * for big RAM machines (>= 384MB), use more for I/O
> > */
> > /*
> > if (total_ram >= MB(384)) {
> > high_queued_sectors = (total_ram * 4) / 5;
> > low_queued_sectors = high_queued_sectors - MB(128);
> > }
> > */
> >
> > Shouldn't it be clean for a 2.4.1 release?
>
> With enough swap the numbers I saw were not conclusive. I promised
> to test which I haven't gotten done yet, I will do this tomorrow
> and make sure we have the right ratios. However, I don't think
> the pre11 numbers are much off - do you have any results?
I have 256 MB RAM and 200 MB swap but nothing of the later was used during
"dbench 48". It was nothing spectacular but a litte bit faster with the above.
Attention: Results only from memory...;-)
Good night.
Dieter
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Re: Linux-2.4.1-pre11 / ll_rw_b watermark metric?
On Mon, Jan 29 2001, Dieter Nützel wrote:
> I have pre11 running with Andrea's suggested fix.
>
> high_queued_sectors = total_ram / 3;
> low_queued_sectors = high_queued_sectors / 2;
> if (low_queued_sectors < 0)
> low_queued_sectors = total_ram / 2;
>
> /*
> * for big RAM machines (>= 384MB), use more for I/O
> */
> /*
> if (total_ram >= MB(384)) {
> high_queued_sectors = (total_ram * 4) / 5;
> low_queued_sectors = high_queued_sectors - MB(128);
> }
> */
>
> Shouldn't it be clean for a 2.4.1 release?
With enough swap the numbers I saw were not conclusive. I promised
to test which I haven't gotten done yet, I will do this tomorrow
and make sure we have the right ratios. However, I don't think
the pre11 numbers are much off - do you have any results?
--
Jens Axboe
-
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: Linux-2.4.1-pre11 / ll_rw_b watermark metric?
I have pre11 running with Andrea's suggested fix.
high_queued_sectors = total_ram / 3;
low_queued_sectors = high_queued_sectors / 2;
if (low_queued_sectors < 0)
low_queued_sectors = total_ram / 2;
/*
* for big RAM machines (>= 384MB), use more for I/O
*/
/*
if (total_ram >= MB(384)) {
high_queued_sectors = (total_ram * 4) / 5;
low_queued_sectors = high_queued_sectors - MB(128);
}
*/
Shouldn't it be clean for a 2.4.1 release?
-Dieter
-
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: Linux-2.4.1-pre11 / ll_rw_b watermark metric?
I have pre11 running with Andrea's suggested fix.
high_queued_sectors = total_ram / 3;
low_queued_sectors = high_queued_sectors / 2;
if (low_queued_sectors 0)
low_queued_sectors = total_ram / 2;
/*
* for big RAM machines (= 384MB), use more for I/O
*/
/*
if (total_ram = MB(384)) {
high_queued_sectors = (total_ram * 4) / 5;
low_queued_sectors = high_queued_sectors - MB(128);
}
*/
Shouldn't it be clean for a 2.4.1 release?
-Dieter
-
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: Linux-2.4.1-pre11 / ll_rw_b watermark metric?
Am Montag, 29. Januar 2001 04:46 schrieb Jens Axboe:
On Mon, Jan 29 2001, Dieter Ntzel wrote:
I have pre11 running with Andrea's suggested fix.
high_queued_sectors = total_ram / 3;
low_queued_sectors = high_queued_sectors / 2;
if (low_queued_sectors 0)
low_queued_sectors = total_ram / 2;
/*
* for big RAM machines (= 384MB), use more for I/O
*/
/*
if (total_ram = MB(384)) {
high_queued_sectors = (total_ram * 4) / 5;
low_queued_sectors = high_queued_sectors - MB(128);
}
*/
Shouldn't it be clean for a 2.4.1 release?
With enough swap the numbers I saw were not conclusive. I promised
to test which I haven't gotten done yet, I will do this tomorrow
and make sure we have the right ratios. However, I don't think
the pre11 numbers are much off - do you have any results?
I have 256 MB RAM and 200 MB swap but nothing of the later was used during
"dbench 48". It was nothing spectacular but a litte bit faster with the above.
Attention: Results only from memory...;-)
Good night.
Dieter
-
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/
