On Tue, Feb 18, 2014 at 2:42 AM, Rajiv Desai <rajiv@xxxxxxxxxxxxxx> wrote: > Some more info: > > Following are mgr:storedir stats after back to back downloads for 4 GB > data (ie same 2 GB twice). > Perhaps the 477 StoreEntries with MemObjects AND 468 Hot Object > Cache Items are not shared? Nah ... those are just the static 53 error etc cached responses per child. 53*9 = 477 > > <stats> > Connection information for squid: > > Number of clients accessing cache: 10 > > Number of HTTP requests received: 78410 > > Number of ICP messages received: 0 > > Number of ICP messages sent: 0 > > Number of queued ICP replies: 0 > > Number of HTCP messages received: 0 > > Number of HTCP messages sent: 0 > > Request failure ratio: 0.00 > > Average HTTP requests per minute since start: 8167.3 > > Average ICP messages per minute since start: 0.0 > > Select loop called: 1228150 times, 4.226 ms avg > > Cache information for squid: > > Hits as % of all requests: 5min: 44.7%, 60min: 44.7% > > Hits as % of bytes sent: 5min: 44.9%, 60min: 44.9% > > Memory hits as % of hit requests: 5min: 0.0%, 60min: 0.0% > > Disk hits as % of hit requests: 5min: 88.9%, 60min: 88.9% > > Storage Swap size: 2454128 KB > > Storage Swap capacity: 1.2% used, 98.8% free > > Storage Mem size: 1980 KB > > Storage Mem capacity: 0.0% used, 0.0% free > > Mean Object Size: 62.81 KB > > Requests given to unlinkd: 0 > > Median Service Times (seconds) 5 min 60 min: > > HTTP Requests (All): 0.03394 0.03394 > > Cache Misses: 0.04430 0.04430 > > Cache Hits: 0.02041 0.02041 > > Near Hits: 0.00000 0.00000 > > Not-Modified Replies: 0.00000 0.00000 > > DNS Lookups: 0.02896 0.02896 > > ICP Queries: 0.00000 0.00000 > > Resource usage for squid: > > UP Time: 576.032 seconds > > CPU Time: 476.166 seconds > > CPU Usage: 82.66% > > CPU Usage, 5 minute avg: 118.39% > > CPU Usage, 60 minute avg: 88.17% > > Process Data Segment Size via sbrk(): 81444 KB > > Maximum Resident Size: 4967328 KB > > Page faults with physical i/o: 2 > > Memory usage for squid via mallinfo(): > > Total space in arena: 82632 KB > > Ordinary blocks: 75092 KB 4345 blks > > Small blocks: 0 KB 0 blks > > Holding blocks: 350592 KB 73 blks > > Free Small blocks: 0 KB > > Free Ordinary blocks: 7540 KB > > Total in use: 7540 KB 2% > > Total free: 7540 KB 2% > > Total size: 433224 KB > > Memory accounted for: > > Total accounted: 27358 KB 6% > > memPool accounted: 27358 KB 6% > > memPool unaccounted: 405866 KB 94% > > memPoolAlloc calls: 17695559 > > memPoolFree calls: 17764839 > > File descriptor usage for squid: > > Maximum number of file descriptors: 589824 > > Largest file desc currently in use: 35 > > Number of file desc currently in use: 135 > > Files queued for open: 0 > > Available number of file descriptors: 589689 > > Reserved number of file descriptors: 900 > > Store Disk files open: 1 > > Internal Data Structures: > > 477 StoreEntries > > 477 StoreEntries with MemObjects > > 468 Hot Object Cache Items > > 39070 on-disk objects > </stats> > > On Tue, Feb 18, 2014 at 1:52 AM, Rajiv Desai <rajiv@xxxxxxxxxxxxxx> wrote: >> Hello, >> >> Need some guidance for optimal sharing of cache amongst SMP workers >> using Large rock. >> >> Context: >> >> I am using squid cache with 8 SMP workers and a 200 GB rock cache stored on SMP. >> (Using squid-3.HEAD-20140127-r13248 which has LargeRock support to >> cache objects > 32 KB). >> >> I have set : >> maximum_object_size 4 MB >> cache_dir rock /mnt/squid-cache 204800 max-size=4194304 >> cache_mem 0 MB >> >> My refresh pattern is very permissive which basically allows caching everything: >> refresh_pattern . 129600 100% 129600 ignore-auth >> >> >> Questions: >> >> I am trying to test optimal caching behavior where after I have >> downloaded 1 GB data (~16000 objects ~64KB each) the subsequent >> download should all be cache hits. >> However, I see several TCP misses in access.log. The hit ratio on >> subsequent download of the same objects is ~85%. >> >> 1. Is this expected in a multiple worker setup? If yes, can you please >> briefly explain what contributes towards these misses and how can this >> be minimized? >> >> 2. I set cache_mem to 0 coz I believe cache_mem sharing is >> opportunistic and hence all workers might not always share all objects >> in cache_mem. Is that correct? What impact does cache_mem size have on >> deterministic sharing of cache between workers. >> >> 3. Moreover are there any tips/guidelines to optimize % hit rate for >> previously downloaded objects. >> >> Thanks, >> Rajiv
