Re: Use ClearSilver in Multi-threading environment?
Brandon Long <[email protected]> Sat, 3 Sep 2011 22:50:54 -1000
| Newsgroups | gmane.text.clearsilver.general |
|---|---|
| Message-ID | <CAA6MhGvLfP06wLtZ1hCpgLLi_uqPdSqqNpC3kpT_o3as4kcBFw@mail.gmail.com> |
--headIyaMMPD6jf1WkIIYqmvUDMf6OHRVzlqNT5U Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On Sat, Sep 3, 2011 at 10:51 AM, Jacky Wang <[email protected]> wro= te: > Hi, > > Thanks for the helps and ClearSilver runs flawlessly on my machine. > > So I'm curiosity on the tips/best practices of its usage under multi-thre= ading environment. > > The sample code is listed as following: > - callback is the function. > - both cs and hdf are shared pointers. > - output is a local ctx pointer. > > <code> > cs->hdf =3D hdf; > cs_render(cs, &output, &callback); =A0// Do I need to put a lock here? > </code> > > My understanding is that if the cs_render actually doesn't change the str= ucture of either cs or hdf, the lock is not needed (thus won't hurt the per= formance). =A0Does it sound? No, this isn't true. I'm sure that CSPARSE contains data structures which are updated on render, and cs commands like set definitely modify hdf. For example, we don't pass the callback around, its actually set in the CSPARSE struct. I guess in theory we could split CSPARSE into both a PARSE and a RENDER struct, so that the PARSE would be read-only for render, but it hasn't been the typical way we've done this. Typically, the parse is somewhat specific to the instance, though I'm sure that's not necessary (jsilver definitely tries to re-use parses, since parsing is expensive. It also means that the equivalent of cs_render in jsilver is thread-safe with a shared cs, but again, HDF isn't thread-safe if the cs render has side affects). From a normal standpoint, cs & hdf are thread safe in the sense that you can use separate instances from separate threads safely, but they are not safe to use from multiple threads at once. There is a concept of a "global HDF", though, which can be loaded and shared across threads, as cs_parse/cs_render treat it as read-only. That isn't to say you can update it from another thread while its being used, but you'd typically load a bunch of data into it at startup, and use it as a read-only structure from that point. The cgi libraries are mostly not thread-safe with the exception of the escape functions. This is because the underlying CGI interface is based on global data (environment variables, stdin & stdout). Since all access to that is through the cgiwrap interface, I've debated making the wrapper thread-safe so that you could "mimic" the CGI interface in a thread-safe fashion, but I'm unsure how useful that would end up being in practice. Brandon --headIyaMMPD6jf1WkIIYqmvUDMf6OHRVzlqNT5U Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/htm= l4/strict.dtd"> <html> <head> </head> <body style=3D"background-color: #fff;"> <span style=3D"display:none"> </span> <!--~-|**|PrettyHtmlStartT|**|-~--> <div id=3D"ygrp-mlmsg" style=3D"position:relative;"> <div id=3D"ygrp-msg" style=3D"z-index: 1;"> <!--~-|**|PrettyHtmlEndT|**|-~--> <div id=3D"ygrp-text" > =20=20=20=20=20=20 =20=20=20=20=20=20 <p>On Sat, Sep 3, 2011 at 10:51 AM, Jacky Wang <<a href=3D"mailto:= jacky.chao.wang%40gmail.com">[email protected]</a>> wrote:<br> > Hi,<br> ><br> > Thanks for the helps and ClearSilver runs flawlessly on my machine.<br= > ><br> > So I'm curiosity on the tips/best practices of its usage under multi-t= hreading environment.<br> ><br> > The sample code is listed as following:<br> > - callback is the function.<br> > - both cs and hdf are shared pointers.<br> > - output is a local ctx pointer.<br> ><br> > <code><br> > cs->hdf =3D hdf;<br> > cs_render(cs, &output, &callback); =A0// Do I need to put a lo= ck here?<br> > </code><br> ><br> > My understanding is that if the cs_render actually doesn't change the = structure of either cs or hdf, the lock is not needed (thus won't hurt the = performance). =A0Does it sound?<br> <br> No, this isn't true. I'm sure that CSPARSE contains data structures<br> which are updated on render, and cs commands like set definitely<br> modify hdf. For example, we don't pass the callback around, its<br> actually set in the CSPARSE struct. I guess in theory we could split<br> CSPARSE into both a PARSE and a RENDER struct, so that the PARSE would<br> be read-only for render, but it hasn't been the typical way we've done<br> this. Typically, the parse is somewhat specific to the instance,<br> though I'm sure that's not necessary (jsilver definitely tries to<br> re-use parses, since parsing is expensive. It also means that the<br> equivalent of cs_render in jsilver is thread-safe with a shared cs,<br> but again, HDF isn't thread-safe if the cs render has side affects).<br> <br> From a normal standpoint, cs & hdf are thread safe in the sense that<br= > you can use separate instances from separate threads safely, but they<br> are not safe to use from multiple threads at once. There is a concept<br> of a "global HDF", though, which can be loaded and shared across<= br> threads, as cs_parse/cs_render treat it as read-only. That isn't to<br> say you can update it from another thread while its being used, but<br> you'd typically load a bunch of data into it at startup, and use it as<br> a read-only structure from that point.<br> <br> The cgi libraries are mostly not thread-safe with the exception of the<br> escape functions. This is because the underlying CGI interface is<br> based on global data (environment variables, stdin & stdout). Since<br= > all access to that is through the cgiwrap interface, I've debated<br> making the wrapper thread-safe so that you could "mimic" the CGI<= br> interface in a thread-safe fashion, but I'm unsure how useful that<br> would end up being in practice.<br> <br> Brandon<br> </p> </div> =20=20=20=20=20 <!--~-|**|PrettyHtmlStart|**|-~--> <div style=3D"color: #fff; height: 0;">__._,_.___</div> =20=20=20=20=20=20=20=20 =20=20 =20=20=20 <div id=3D"ygrp-actbar" style=3D"clear: both; margin-bottom: 10px; whit= e-space: nowrap; color: #666; padding-top: 15px;"> <div> <a href=3D"mailto:[email protected]?subject=3DRe%3A%20Use%20ClearSi= lver%20in%20Multi-threading%20environment%3F" style=3D"margin-right: 0; pad= ding-right: 0;"> Reply to <span style=3D"font-weight: 700;">sender</span></a> | <a href=3D"mailto:[email protected]?subject=3DRe%3A%20Use= %20ClearSilver%20in%20Multi-threading%20environment%3F"> Reply to <span style=3D"font-weight: 700;">group</span></a> | <a href=3D"http://groups.yahoo.com/group/ClearSilver/post;_ylc= =3DX3oDMTJwbHI2dm1oBF9TAzk3MzU5NzE0BGdycElkAzM1NjQxMzcEZ3Jwc3BJZAMxNzA3Mjgx= OTQyBG1zZ0lkAzE0MTQEc2VjA2Z0cgRzbGsDcnBseQRzdGltZQMxMzE1MTI2MjU4?act=3Drepl= y&messageNum=3D1414">Reply <span style=3D"font-weight: 700;">via web post</= span></a> | <a href=3D"http://groups.yahoo.com/group/ClearSilver/post;_ylc= =3DX3oDMTJlaDJ0ZjI0BF9TAzk3MzU5NzE0BGdycElkAzM1NjQxMzcEZ3Jwc3BJZAMxNzA3Mjgx= OTQyBHNlYwNmdHIEc2xrA250cGMEc3RpbWUDMTMxNTEyNjI1OA--" style=3D"font-weight:= 700;">Start a New Topic</a> </div> <a href=3D"http://groups.yahoo.com/group/ClearSilver/messag= e/1412;_ylc=3DX3oDMTM0Y2tkZWI5BF9TAzk3MzU5NzE0BGdycElkAzM1NjQxMzcEZ3Jwc3BJZ= AMxNzA3MjgxOTQyBG1zZ0lkAzE0MTQEc2VjA2Z0cgRzbGsDdnRwYwRzdGltZQMxMzE1MTI2MjU4= BHRwY0lkAzE0MTI-">Messages in this topic</a> (<span style=3D"font-weight: 700;">2</span>) </div>=20 <!------- Start Nav Bar ------> <!-- |**|begin egp html banner|**| --> <div id=3D"ygrp-vital" style=3D"background-color: #e0ecee; font-family: Ver= dana; font-size: 10px; margin-bottom: 10px; padding: 10px;"> <span id=3D"vithd" style=3D"font-weight: bold; color: #333; text-tran= sform: uppercase; ">Recent Activity:</span> <ul style=3D"list-style-type: none; margin: 0; padding: 0; display: inl= ine;"> <li style=3D"border-right: 1px solid #000; font-weight: 700; di= splay: inline; padding: 0 5px; margin-left: 0;"> <span class=3D"cat"><a href=3D"http://groups.yahoo.com/group/ClearSil= ver/members;_ylc=3DX3oDMTJmNnNsZTBmBF9TAzk3MzU5NzE0BGdycElkAzM1NjQxMzcEZ3Jw= c3BJZAMxNzA3MjgxOTQyBHNlYwN2dGwEc2xrA3ZtYnJzBHN0aW1lAzEzMTUxMjYyNTg-?o=3D6"= style=3D"text-decoration: none;">New Members</a></span> <span class=3D"ct" style=3D"color: #ff7900;">1</span> </li> </ul> =20=20=20=20 <div style=3D"clear: both; padding-top: 2px; color: #1e66ae;"> <a href=3D"http://groups.yahoo.com/group/ClearSilver;_ylc=3DX3oDMTJlOTZ= zdmVmBF9TAzk3MzU5NzE0BGdycElkAzM1NjQxMzcEZ3Jwc3BJZAMxNzA3MjgxOTQyBHNlYwN2dG= wEc2xrA3ZnaHAEc3RpbWUDMTMxNTEyNjI1OA--" style=3D"text-decoration: none;">Vi= sit Your Group</a> </div> </div> <div id=3D"ygrp-mkp" style=3D"border: 1px solid #d8d8d8; clea= r: both; float: left; font-family: Arial; margin: 5px 0 10px 0; padding: 0 = 10px;"> <div id=3D"hd" style=3D"color: #628c2a; font-size: 85%; font-weight: = 700; line-height: 122%; margin: 10px 0;">MARKETPLACE</div> <div id=3D"ads" style=3D"margin-bottom: 10px;"> <div class=3D"ad" style=3D"color: #628C2A; font-family: A= rial; font-weight: 700; padding: 0 0;"> <a href=3D"http://global.ard.yahoo.com/SIG=3D15ovub31i/M=3D7917= 26.14847541.14590405.10835568/D=3Dgroups/S=3D1707281942:MKP1/Y=3DYAHOO/EXP= =3D1315133458/L=3D020d31a6-d6d3-11e0-bcd4-274826888193/B=3Ds0TQQGKJiU0-/J= =3D1315126258216045/K=3DA8LGQxof4LPwPq6gWRc__g/A=3D6475085/R=3D0/SIG=3D1309= nvt92/*http://www.freecreditscore.com/dni/default.aspx?SiteVersionID=3D997&= sc=3D671266&bcd=3DYGROUPS_Bad579">A bad score is 579. 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