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From: "Alex Bennée" <alex.bennee@linaro.org>
To: Thomas <74cmonty@gmail.com>
Cc: "Paul Zimmerman" <pauldzim@gmail.com>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	qemu-arm <qemu-arm@nongnu.org>,
	"QEMU Developers" <qemu-devel@nongnu.org>,
	"Andrew Baumann" <Andrew.Baumann@microsoft.com>,
	"Philippe Mathieu-Daudé" <f4bug@amsat.org>
Subject: Re: Emulate Rpi with QEMU fails
Date: Fri, 09 Oct 2020 07:20:43 +0100	[thread overview]
Message-ID: <874kn3zzr8.fsf@linaro.org> (raw)
In-Reply-To: <2e3754fb-8b3c-4ef2-989f-a0015ef3a7e8@gmail.com>


Thomas <74cmonty@gmail.com> writes:

> Interesting enough is: my top figure reported by perf is like yours:
>
> Samples: 6M of event 'cycles:u', Event count (approx.): 1936571734942
> Overhead  Command          Shared Object                  Symbol
>    7,95%  qemu-system-arm  qemu-system-arm                [.]
> helper_lookup_tb_ptr                                                        
> ◆
>    4,16%  qemu-system-arm  qemu-system-arm                [.]
> cpu_get_tb_cpu_state                                                        
> ▒

Not quite - cpu_get_tb_state should be a fair bit cheaper now since the
optimisations to hflags where introduced.

>    2,52%  qemu-system-arm  libpthread-2.32.so             [.]
> __pthread_mutex_lock                                                        
> ▒

This indicated there is some lock contention. The QSP profiler can
help here.

Are you running the latest state of master?

-- 
Alex Bennée

WARNING: multiple messages have this Message-ID (diff)
From: "Alex Bennée" <alex.bennee@linaro.org>
To: Thomas <74cmonty@gmail.com>
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
	"Philippe Mathieu-Daudé" <f4bug@amsat.org>,
	"Andrew Baumann" <Andrew.Baumann@microsoft.com>,
	"QEMU Developers" <qemu-devel@nongnu.org>,
	qemu-arm <qemu-arm@nongnu.org>,
	"Paul Zimmerman" <pauldzim@gmail.com>
Subject: Re: Emulate Rpi with QEMU fails
Date: Fri, 09 Oct 2020 07:20:43 +0100	[thread overview]
Message-ID: <874kn3zzr8.fsf@linaro.org> (raw)
In-Reply-To: <2e3754fb-8b3c-4ef2-989f-a0015ef3a7e8@gmail.com>


Thomas <74cmonty@gmail.com> writes:

> Interesting enough is: my top figure reported by perf is like yours:
>
> Samples: 6M of event 'cycles:u', Event count (approx.): 1936571734942
> Overhead  Command          Shared Object                  Symbol
>    7,95%  qemu-system-arm  qemu-system-arm                [.]
> helper_lookup_tb_ptr                                                        
> ◆
>    4,16%  qemu-system-arm  qemu-system-arm                [.]
> cpu_get_tb_cpu_state                                                        
> ▒

Not quite - cpu_get_tb_state should be a fair bit cheaper now since the
optimisations to hflags where introduced.

>    2,52%  qemu-system-arm  libpthread-2.32.so             [.]
> __pthread_mutex_lock                                                        
> ▒

This indicated there is some lock contention. The QSP profiler can
help here.

Are you running the latest state of master?

-- 
Alex Bennée


  parent reply	other threads:[~2020-10-09  6:20 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-03 11:45 Emulate Rpi with QEMU fails Thomas
2020-10-04 17:44 ` Alex Bennée
2020-10-04 17:44   ` Alex Bennée
2020-10-04 18:40   ` Peter Maydell
2020-10-04 18:40     ` Peter Maydell
2020-10-05  9:40     ` Alex Bennée
2020-10-05  9:40       ` Alex Bennée
2020-10-05 10:51       ` Thomas Schneider
2020-10-05 22:08         ` Paul Zimmerman
2020-10-05 22:08           ` Paul Zimmerman
2020-10-06  6:58           ` Thomas Schneider
2020-10-06  6:58             ` Thomas Schneider
2020-10-06  7:42             ` Paul Zimmerman
2020-10-06  7:42               ` Paul Zimmerman
2020-10-06  9:58             ` Alex Bennée
2020-10-06  9:58               ` Alex Bennée
2020-10-07  6:28               ` Thomas
2020-10-07  6:28                 ` Thomas
2020-10-07  6:50                 ` Paul Zimmerman
2020-10-07  6:50                   ` Paul Zimmerman
2020-10-07  7:27                   ` Thomas Schneider
2020-10-07  7:27                     ` Thomas Schneider
2020-10-07 11:00                     ` Alex Bennée
2020-10-07 11:00                       ` Alex Bennée
2020-10-07 11:36                       ` Thomas Schneider
2020-10-07 11:36                         ` Thomas Schneider
2020-10-07 12:02                         ` Alex Bennée
2020-10-07 12:02                           ` Alex Bennée
2020-10-08  7:00                           ` Thomas
2020-10-08  7:00                             ` Thomas
2020-10-08 21:07                             ` Paul Zimmerman
2020-10-08 21:07                               ` Paul Zimmerman
2020-10-09  2:21                               ` Paul Zimmerman
2020-10-09  2:21                                 ` Paul Zimmerman
2020-10-09  6:20                             ` Alex Bennée [this message]
2020-10-09  6:20                               ` Alex Bennée

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