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Date: Thu, 10 Dec 2015 09:42:59 +0000
Message-ID: <CAF6XsOeYWvuNm=uuMCM4YD4a2dCoBe6TvimygPKRe4PMiHwQmw@mail.gmail.com>
Subject: Page Cache Monitoring ( Hit/Miss )
From: Allan McAleavy <allan.mcaleavy@gmail.com>
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--001a114017c645d3bb052688085e
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Hi Folks,

I am working on a rewrite of Brendan Greggs original cachestat (ftrace)
script into bcc. What I was looking for was a steer in the right direction
for what functions to trace. At present I trace the following.

add_to_page_cache_lru
account_page_dirtied
mark_page_accessed
mark_buffer_dirty

Where total = (mark_page_accessed - mark_buffer_dirty) & misses =
(add_to_page_cache_lru - account_page_dirtied), from this I then work out
the hit ratio etc. Is there any other key functions I should be tracing?

Thanks

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Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr"><font face=3D"Menlo" style=3D"font-size:12.8px">Hi Folks,<=
/font><div style=3D"font-size:12.8px"><font face=3D"Menlo"><br></font></div=
><div style=3D"font-size:12.8px"><font face=3D"Menlo">I am working on a rew=
rite of Brendan Greggs original cachestat (ftrace) script into bcc. What I =
was looking for was a steer in the right direction for what functions to tr=
ace. At present I trace the following.=C2=A0</font></div><div style=3D"font=
-size:12.8px"><font face=3D"Menlo"><br></font></div><div style=3D"font-size=
:12.8px"><font face=3D"Menlo">add_to_page_cache_lru</font></div><div style=
=3D"font-size:12.8px"><div style=3D"margin:0px"><span style=3D"font-family:=
Menlo">account_page_dirtied</span></div><div style=3D"margin:0px"><font fac=
e=3D"Menlo">mark_page_accessed</font></div><div style=3D"margin:0px"><span =
style=3D"font-family:Menlo">mark_buffer_dirty</span></div><div style=3D"mar=
gin:0px"><font face=3D"Menlo"><br></font></div></div><div style=3D"font-siz=
e:12.8px;margin:0px"><font face=3D"Menlo">Where total =3D (mark_page_access=
ed - mark_buffer_dirty) &amp; misses =3D (add_to_page_cache_lru - account_p=
age_dirtied), from this I then work out the hit ratio etc. Is there any oth=
er key functions I should be tracing?</font></div><div style=3D"font-size:1=
2.8px;margin:0px"><font face=3D"Menlo"><br></font></div><div style=3D"font-=
size:12.8px;margin:0px"><font face=3D"Menlo">Thanks</font></div></div>

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