* New pty implementation is really slow
@ 2020-03-22 3:21 Joe
2020-03-22 5:51 ` Marco Atzeri
0 siblings, 1 reply; 3+ messages in thread
From: Joe @ 2020-03-22 3:21 UTC (permalink / raw)
To: cygwin
I'm using cygwin 3.1.4 on Windows 10.
The new pseudo terminal stuff seems really slow.
For example:
$ time seq 10000
(output omitted)
real 0m23.510s
user 0m1.515s
sys 0m4.483s
If I minimize the mintty window while seq is running, it gets slightly better:
real 0m4.562s
user 0m0.390s
sys 0m1.202s
But when I set CYGWIN=disable_pcon before starting mintty, I get:
$ time seq 10000
(output omitted)
real 0m0.366s
user 0m0.109s
sys 0m0.093s
So the new implementation seems to be over 60 times slower than the old one.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: New pty implementation is really slow
2020-03-22 3:21 New pty implementation is really slow Joe
@ 2020-03-22 5:51 ` Marco Atzeri
2020-03-22 7:43 ` Thomas Wolff
0 siblings, 1 reply; 3+ messages in thread
From: Marco Atzeri @ 2020-03-22 5:51 UTC (permalink / raw)
To: cygwin
Am 22.03.2020 um 04:21 schrieb Joe via Cygwin:
> I'm using cygwin 3.1.4 on Windows 10.
>
> The new pseudo terminal stuff seems really slow.
>
> For example:
> $ time seq 10000
> (output omitted)
> real 0m23.510s
> user 0m1.515s
> sys 0m4.483s
>
> If I minimize the mintty window while seq is running, it gets slightly better:
> real 0m4.562s
> user 0m0.390s
> sys 0m1.202s
>
> But when I set CYGWIN=disable_pcon before starting mintty, I get:
> $ time seq 10000
> (output omitted)
> real 0m0.366s
> user 0m0.109s
> sys 0m0.093s
>
> So the new implementation seems to be over 60 times slower than the old one.
> --
only factor 10x on my test, amd only impacting mintty case
Curious that 32bit disabled is 2x faster than 64bit disabled
64 bit
Mintty with enabled (default)
real 0m2.674s
user 0m0.234s
sys 0m0.859s
mintty with disabled
real 0m0.247s
user 0m0.015s
sys 0m0.046s
CMD with enabled
real 0m1.121s
user 0m0.109s
sys 0m0.187s
CMD with disabled
real 0m1.084s
user 0m0.078s
sys 0m0.312s
32 bit
Mintty with enabled (default)
real 0m2.548s
user 0m0.281s
sys 0m0.686s
Mintty with disabled
real 0m0.058s
user 0m0.030s
sys 0m0.000s
CMD with enabled
real 0m1.021s
user 0m0.124s
sys 0m0.296s
CMD with disabled
real 0m1.018s
user 0m0.109s
sys 0m0.265s
I have the impression that the slow is due to some type of buffer
expansion as I seem to notice a not uniform progress of the print
the screen. But it could be just my eye...
$ uname -svr
CYGWIN_NT-10.0 3.1.4(0.340/5/3) 2020-02-19 08:49
Regards
Marco
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: New pty implementation is really slow
2020-03-22 5:51 ` Marco Atzeri
@ 2020-03-22 7:43 ` Thomas Wolff
0 siblings, 0 replies; 3+ messages in thread
From: Thomas Wolff @ 2020-03-22 7:43 UTC (permalink / raw)
To: cygwin
Am 22.03.2020 um 06:51 schrieb Marco Atzeri via Cygwin:
> Am 22.03.2020 um 04:21 schrieb Joe via Cygwin:
>> I'm using cygwin 3.1.4 on Windows 10.
>>
>> The new pseudo terminal stuff seems really slow.
>>
>> For example:
>> $ time seq 10000
>> (output omitted)
>> real 0m23.510s
>> user 0m1.515s
>> sys 0m4.483s
>>
>> If I minimize the mintty window while seq is running, it gets
>> slightly better:
>> real 0m4.562s
>> user 0m0.390s
>> sys 0m1.202s
>>
>> But when I set CYGWIN=disable_pcon before starting mintty, I get:
>> $ time seq 10000
>> (output omitted)
>> real 0m0.366s
>> user 0m0.109s
>> sys 0m0.093s
>>
>> So the new implementation seems to be over 60 times slower than the
>> old one.
>> --
>
> only factor 10x on my test, amd only impacting mintty case
> Curious that 32bit disabled is 2x faster than 64bit disabled
>
> 64 bit
>
> Mintty with enabled (default)
>
> real 0m2.674s
> user 0m0.234s
> sys 0m0.859s
>
> mintty with disabled
>
> real 0m0.247s
> user 0m0.015s
> sys 0m0.046s
>
> CMD with enabled
> real 0m1.121s
> user 0m0.109s
> sys 0m0.187s
>
> CMD with disabled
> real 0m1.084s
> user 0m0.078s
> sys 0m0.312s
>
> 32 bit
>
> Mintty with enabled (default)
> real 0m2.548s
> user 0m0.281s
> sys 0m0.686s
>
> Mintty with disabled
> real 0m0.058s
> user 0m0.030s
> sys 0m0.000s
>
> CMD with enabled
> real 0m1.021s
> user 0m0.124s
> sys 0m0.296s
>
> CMD with disabled
> real 0m1.018s
> user 0m0.109s
> sys 0m0.265s
>
> I have the impression that the slow is due to some type of buffer
> expansion as I seem to notice a not uniform progress of the print
> the screen. But it could be just my eye...
With disable_pcon, output is sent to mintty in bunches of 256 bytes at
each read() invocation.
With pcon enabled, typical output size is 12 bytes. That doesn't seem to
be the whole story, though.
Thomas
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-03-22 3:21 New pty implementation is really slow Joe
2020-03-22 5:51 ` Marco Atzeri
2020-03-22 7:43 ` Thomas Wolff
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